The monthly income of two persons is in the ratio 4:5 and their expenditures are in the ratio 7:9. If each saves ₹50 per month, then their monthly incomes are:
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Answer: (A) 400; 500
Explanation
Let the monthly incomes of the two persons be 4x and 5x.
Since both persons save ₹50 per month, their expenditures are 4x - 50 and 5x - 50 respectively.
The ratio of their expenditures is given as 7:9. Setting up the equation:
(4x - 50) / (5x - 50) = 7/9
Cross-multiplying the terms:
9 × (4x - 50) = 7 × (5x - 50)
36x - 450 = 35x - 350
Subtracting 35x from both sides and adding 450 to both sides:
x = 100
Substituting the value of x back into the income terms:
First person's income = 4 × 100 = 400
Second person's income = 5 × 100 = 500
352Quantitative Aptitude
Study the given table and answer the question that follow.
The following table gives the month- wise number of different types of scooters produced by a company during the first six months of 1992.
Months of scooters | JANUARY | FEBRUARY | MARCH | APRIL | MAY | JUNE
X | 25 | 25 | 18 | 40 | 20 | 15
Y | 25 | 27 | 50 | 45 | 30 | 20
Z | 25 | 27 | 15 | 25 | 30 | 20
T | 25 | 26 | 25 | 0 | 30 | 35
TOTAL | 100 | 105 | 108 | 110 | 110 | 90
What is the total number of scooters of all the four types taken together that was produced by the company during the first six months of 1992?
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Answer: (A) 623
Explanation
To find the total number of scooters of all four types produced by the company during the first six months of 1992, we sum the total production values given for each of the six months:
Total Production = January + February + March + April + May + June
Substituting the monthly totals from the table:
Total Production = 100 + 105 + 108 + 110 + 110 + 90
Total Production = 623
353Quantitative Aptitude
The population of a country has been declining at 1% every decade. If the projected population of the country in 2030 is given as 1940598, what was the population of the country in 2000?
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Answer: (A) 2000000
Explanation
Let the population of the country in 2000 be P₀.
The population declines at a rate of 1% (r = 0.01) every decade. The time duration from 2000 to 2030 is 30 years, which corresponds to exactly 3 decades (n = 3).
The population after n decades is given by the compounding decline formula:
P_n = P₀ × (1 - r)ⁿ
Substituting the given values:
1940598 = P₀ × (1 - 0.01)³
1940598 = P₀ × (0.99)³
To pack a set of books, Gautam got cartons of a certain height that were 48 inches long and 27 inches wide. If the volume of such a carton was 22.5 cubic feet, what was the height of each carton? [Use 1 foot = 12 inches.]
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Answer: (C) 30 inches
Explanation
Volume of a rectangular carton is given by the formula:
Volume = length × width × height
First, convert the dimensions of the carton from inches to feet:
Length = 48/12 = 4 feet
Width = 27/12 = 2.25 feet
Convert the height back to inches:
Height = 2.5 × 12 = 30 inches
357Quantitative Aptitude
5 kg of ₹18 per kg wheat is mixed with 2 kg of another type of wheat to get a mixture costing ₹20 per kg. Find the price (per kg) of the costlier wheat.
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Answer: (B) 25
Explanation
By the weighted average formula, the total cost of the mixture is the sum of the costs of its individual components:
(W₁ × P₁) + (W₂ × P₂) = (W₁ + W₂) × P_m
where W₁ and W₂ are the weights of the two types of wheat, P₁ and P₂ are their respective prices per kg, and P_m is the price per kg of the final mixture.
Given:
W₁ = 5 kg, P₁ = ₹18
W₂ = 2 kg
P_m = ₹20
Let P₂ be the price per kg of the costlier wheat:
(5 × 18) + (2 × P₂) = (5 + 2) × 20
90 + 2P₂ = 7 × 20
90 + 2P₂ = 140
2P₂ = 50
P₂ = 25
358Quantitative Aptitude
If cot 75° = 2 - √3. Find the value of cot 15°.
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Answer: (B) 2 + √3
Explanation
Using the complementary angle identity, cot θ = tan(90° - θ).
For θ = 15°:
cot 15° = tan(90° - 15°) = tan 75°
Since tan 75° = 1 / cot 75°, substitute the given value:
cot 15° = 1 / (2 - √3)
To simplify, rationalize the denominator by multiplying the numerator and the denominator by the conjugate 2 + √3:
cot 15° = (2 + √3) / ((2 - √3)(2 + √3))
cot 15° = (2 + √3) / (2² - (√3)²)
cot 15° = (2 + √3) / (4 - 3)
cot 15° = 2 + √3
359Quantitative Aptitude
In a government scheme, if an electricity bill is paid before the due date, one gets a reduction of 5% on the amount of the bill. By paying the bill before the due date, a person got a reduction of ₹20. The amount of his electricity bill was:
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Answer: (B) 400
Explanation
Let the amount of the electricity bill be x.
The reduction obtained is 5% of the bill amount, which is given as ₹20. Using the percentage relation:
5% of x = 20
(5 / 100) × x = 20
x = (20 × 100) / 5
x = 400
360Quantitative Aptitude
A shopkeeper earns a profit of 12% on selling a book at 10% discount on the printed price. The ratio of the cost price to the printed price is:
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Answer: (B) 45:56
Explanation
The relationship between the cost price (CP) and the printed price (MP) when the discount percentage (D) and profit percentage (P) are known is given by the formula:
CP / MP = (100 - D) / (100 + P)
Substituting the given values of D = 10 and P = 12 into the formula:
CP / MP = (100 - 10) / (100 + 12)
CP / MP = 90 / 112
Simplifying the fraction by dividing both the numerator and the denominator by 2 yields 45/56, which represents the ratio 45:56.
361Quantitative Aptitude
A thief was spotted by a policeman from a distance of 225 metres. When the policeman started the chase, the thief also started running. If the speed of the thief was 11 km/h and that of the policeman was 13 km/h, how far would the thief have run, before the policeman caught up with him?
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Answer: (A) 1237.5 metres
Explanation
Since the policeman and the thief run for the exact same duration of time until the chase ends, the distance covered by each is directly proportional to their respective speeds.
Ratio of distance covered by the policeman to the thief = Ratio of their speeds = 13 : 11
Let the distance covered by the policeman be 13x and the distance covered by the thief be 11x. The difference between these distances is the initial gap of 225 metres:
13x - 11x = 225
2x = 225
x = 112.5 metres
The distance run by the thief before being caught is:
11x = 11 × 112.5 = 1237.5 metres
362Quantitative Aptitude
Which of the following is divisible by 3?
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Answer: (A) 7345932
Explanation
According to the divisibility rule of 3, a number is completely divisible by 3 if the sum of its individual digits is divisible by 3.
For the number 7345932, the sum of the digits is:
7 + 3 + 4 + 5 + 9 + 3 + 2 = 33
Since 33 is a multiple of 3 (3 × 11 = 33), the number 7345932 is divisible by 3.
363Quantitative Aptitude
At a certain rate of interest compounded annually, a sum amounts to ₹10,890 in 2 years and to ₹11,979 in 3 years. The sum is:
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Answer: (A) 9,000
Explanation
The amount A after n years at a compound interest rate of r% per annum on a principal sum P is given by the formula:
A = P(1 + r/100)ⁿ
Using the given values for 2 years and 3 years:
10,890 = P(1 + r/100)²
11,979 = P(1 + r/100)³
Dividing the equation for 3 years by the equation for 2 years gives the multiplier for one year:
1 + r/100 = 11,979 / 10,890
1 + r/100 = 1.1
Substituting this value back into the equation for 2 years:
P × (1.1)² = 10,890
P × 1.21 = 10,890
P = 10,890 / 1.21
P = 9,000
364Quantitative Aptitude
If x = 32, y = 33 and z = 35, then evaluate the expression x³ + y³ + z³ - 3xyz.
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Answer: (D) 700
Explanation
The algebraic identity for the given expression is:
x³ + y³ + z³ - 3xyz = ½(x + y + z)[(x - y)² + (y - z)² + (z - x)²]
Substituting the given values x = 32, y = 33, and z = 35 into this formula:
First, calculate the sum of the variables:
x + y + z = 32 + 33 + 35 = 100
Substitute these values back into the identity:
½ × 100 × 14 = 50 × 14 = 700
365Quantitative Aptitude
In a class, there are 39 students and their average weight is 51 kg. If we include the weight of the teacher, then the average weight becomes 51.2 kg. What is the weight of the teacher?
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Answer: (B) 59 kg
Explanation
The weight of the teacher can be calculated directly using the average deviation formula:
Weight of the teacher = Old average + (New total number of people × Increase in average)
Here, the old average is 51 kg. When the teacher is included, the total number of people becomes 39 + 1 = 40, and the average increases by 51.2 - 51 = 0.2 kg.
Substituting these values:
Weight of the teacher = 51 + (40 × 0.2) = 51 + 8 = 59 kg.
366Quantitative Aptitude
A sum of money becomes ₹ 3,364 at a rate of 16% compounded annually for 2 years. The sum of money is:
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Answer: (A) 2500
Explanation
The formula for the amount accrued under annual compound interest is:
A = P(1 + R/100)ⁿ
Here, the amount A is ₹ 3364, the rate of interest R is 16%, and the time period n is 2 years. Substituting these values into the formula:
3364 = P(1 + 16/100)²
3364 = P(1 + 4/25)²
3364 = P(29/25)²
3364 = P × 841/625
P = (3364 × 625) / 841
P = 4 × 625
P = 2500
367Quantitative Aptitude
If the surface area of a sphere is 1386 cm², then find the radius of the sphere.
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Answer: (B) 10.5 cm
Explanation
The surface area of a sphere is given by the formula 4πr², where r represents the radius of the sphere.
Substituting the given surface area of 1386 cm² and using the value of π as 22/7:
4 × (22/7) × r² = 1386
Rearranging the terms to solve for r²:
r² = (1386 × 7) / (4 × 22)
r² = (63 × 7) / 4
r² = 441 / 4
Taking the square root on both sides:
r = √(441 / 4)
r = 21/2
r = 10.5 cm
368Quantitative Aptitude
Simplify (957 + 932)² - 4 × 957 × 932.
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Answer: (D) 625
Explanation
Using the algebraic identity (a + b)² - 4ab = (a - b)², we can simplify the expression by substituting a = 957 and b = 932.
This gives:
(957 - 932)² = 25² = 625
This yields the simplified value directly.
369Quantitative Aptitude
In what ratio must a shopkeeper mix two types of rice worth ₹60 per kg and ₹80 per kg, so that the average cost of the mixture is ₹75 per kg?
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Answer: (A) 1:3
Explanation
Using the rule of alligation, the ratio of the quantity of cheaper rice to the quantity of dearer rice is calculated as:
Ratio = (Price of dearer rice - Mean price) / (Mean price - Price of cheaper rice)
Substituting the given values:
Ratio = (80 - 75) / (75 - 60) = 5 / 15 = 1 / 3
This simplifies to 1:3.
370Quantitative Aptitude
In an election between two candidates, 80% of the eligible voters cast their votes, 5% of the votes cast were declared invalid. A candidate got 10545 votes, which were 75% of the total valid votes. Find the total number of eligible voters.
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Answer: (B) 18500
Explanation
Let the total number of eligible voters be V.
Number of votes cast = 80% of V = (4/5) × V
Number of valid votes = 95% of the cast votes = (19/20) × (4/5) × V
Number of votes secured by the candidate = 75% of the valid votes = (3/4) × (19/20) × (4/5) × V
We are given that this value is equal to 10545:
(3/4) × (19/20) × (4/5) × V = 10545
Canceling 4 in the numerator and denominator:
V × (19 × 3) / (20 × 5) = 10545
V × 57 / 100 = 10545
V = (10545 × 100) / 57
V = 185 × 100 = 18500
371Quantitative Aptitude
A can do ⅕ of the work in 3 days and B can do ¼ of the work in 7.5 days. Working together, A and B can do ⅘ of the same work in:
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Answer: (C) 8 days
Explanation
Time taken by A to complete the whole work is 3 × 5 = 15 days.
Time taken by B to complete the whole work is 7.5 × 4 = 30 days.
Taking the least common multiple of 15 and 30, let the total work be 30 units.
Efficiency of A = 30 / 15 = 2 units per day.
Efficiency of B = 30 / 30 = 1 unit per day.
Combined efficiency of A and B = 2 + 1 = 3 units per day.
The required amount of work to be completed is 4/5 of the total work:
4/5 × 30 = 24 units.
The number of days required by A and B working together to complete this work:
24 / 3 = 8 days.
372Quantitative Aptitude
What is the value of (1¼÷ 2⅗)÷ 1⁷⁄₁₃?
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Answer: (B) ⁵⁄₁₆
Explanation
Convert the mixed fractions into improper fractions:
1 ¼ = 5/4
2 ⅗ = 13/5
1 ⁷/₁₃ = 20/13
Now, substitute these fractions back into the given expression:
(5/4 ÷ 13/5) ÷ 20/13
Perform the operations inside the parentheses first:
5/4 ÷ 13/5 = 5/4 × 5/13 = 25/52
Next, divide the result by the remaining fraction:
25/52 ÷ 20/13 = 25/52 × 13/20
Simplify the expression by canceling out common terms:
(25 × 13) / (52 × 20) = (5 × 5 × 13) / (4 × 13 × 4 × 5) = 5 / (4 × 4) = 5/16
373Quantitative Aptitude
The monthly income of a person was Rs12,000 and his monthly expenditure was Rs10,000. In the next year, his income increased by 12% and his expenditure by 5% Find the percentage increase in his savings.
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Answer: (C) 47%
Explanation
Income equals the sum of expenditure and savings.
Initial savings = Income - Expenditure = 12,000 - 10,000 = 2,000.
The ratio of expenditure to savings is 10,000 : 2,000 = 5 : 1.
Using the weighted average formula for percentage changes:
Percentage increase in Income = (Ratio of Expenditure × Percentage increase in Expenditure + Ratio of Savings × Percentage increase in Savings) / Total Ratio
Let the percentage increase in savings be x%.
12% = (5 × 5% + 1 × x%) / (5 + 1)
12% × 6 = 25% + x%
72% = 25% + x%
x% = 47%
374Quantitative Aptitude
If (x + ¹⁄ₓ) = 8.5, what is the value of (x² + (1)/(x²))?
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Answer: (A) 70.25
Explanation
The algebraic identity for the square of a binomial is:
(a + b)² = a² + b² + 2ab
Letting a = x and b = 1/x, we get:
(x + 1/x)² = x² + 1/x² + 2(x)(1/x)
(x + 1/x)² = x² + 1/x² + 2
Rearranging the formula to solve for x² + 1/x²:
x² + 1/x² = (x + 1/x)² - 2
Substituting the given value of x + 1/x = 8.5 into the equation:
x² + 1/x² = (8.5)² - 2
x² + 1/x² = 72.25 - 2
x² + 1/x² = 70.25
375Quantitative Aptitude
The table below gives the numbers of students from five different colleges who participated in Olympiads of five different subjects during a given year.
| Subjects | College A | College B | College C | College D | College E |
|---|---|---|---|---|---|
| Hindi | 110 | 100 | 125 | 103 | 112 |
| English | 98 | 120 | 80 | 122 | 105 |
| Maths | 130 | 110 | 250 | 160 | 180 |
| Science | 100 | 100 | 150 | 200 | 80 |
| GK | 182 | 200 | 120 | 130 | 183 |
Find the difference between the range of the numbers of participants in the different Olympiads from College C and the average number of participants per Olympiad from College E during the given year.
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Answer: (B) 38
Explanation
For College C, the number of participants across the five subjects are 125 in Hindi, 80 in English, 250 in Maths, 150 in Science, and 120 in GK. The range is the difference between the maximum and minimum values. The maximum number of participants is 250 and the minimum is 80. Thus, the range of participants from College C is 250 - 80 = 170.
For College E, the number of participants across the five subjects are 112 in Hindi, 105 in English, 180 in Maths, 80 in Science, and 183 in GK. The sum of these participants is 112 + 105 + 180 + 80 + 183 = 660. Since there are 5 subjects, the average number of participants per Olympiad from College E is 660 ÷ 5 = 132.
The required difference between the range of College C and the average of College E is 170 - 132 = 38.
376Quantitative Aptitude
The Group Leader of a group of 6 students reported that their average weight is 46 kg. When the members of the group were asked about their individual weights, 5 of them answered: 50 kg, 52 kg, 40 kg, 44 kg, 48 kg. The 6th member said, "I can't recall my weight". What is his weight?
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Answer: (D) 42 kg
Explanation
Total weight of the 6 students can be calculated using the average weight formula:
Total weight = Average weight × Number of students
Total weight = 46 × 6 = 276 kg
The sum of the weights of the five students who recall their weight is:
50 + 52 + 40 + 44 + 48 = 234 kg
The weight of the 6th student is the difference between the total weight of the group and the sum of the weights of the other five students:
Weight of the 6th student = 276 - 234 = 42 kg
377Quantitative Aptitude
What will be the smallest natural number to be filled in the blank for the number '23_45678' to be divisible by 22?
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Answer: (A) 7
Explanation
For a number to be divisible by 22, it must be divisible by both 2 and 11.
Since the last digit of 23₄5678 is 8, the number is even and thus always divisible by 2.
For divisibility by 11, the difference between the sum of the digits at odd positions and the sum of the digits at even positions must be 0 or a multiple of 11. Let the blank space be represented by the digit x.
Sum of digits at odd positions from the left = 2 + x + 5 + 7 = 14 + x
Sum of digits at even positions from the left = 3 + 4 + 6 + 8 = 21
The difference between these sums is (21) - (14 + x) = 7 - x.
For this difference to be a multiple of 11 (in this case, 0), we set 7 - x = 0, which yields x = 7. Since 7 is a natural number, it is the correct value to fill the blank.
378Quantitative Aptitude
If the cost price of 70 articles is equal to the selling price of 40 articles, what will be the profit percentage?
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Answer: (A) 75%
Explanation
Let the cost price of 1 article be CP and the selling price of 1 article be SP.
We are given that the cost price of 70 articles is equal to the selling price of 40 articles:
70 × CP = 40 × SP
Rearranging the terms gives the ratio of the selling price to the cost price:
SP / CP = 70 / 40 = 7 / 4
This means if the cost price is 4 units, the selling price is 7 units.
The profit is the difference between the selling price and the cost price:
Profit = SP - CP = 7 - 4 = 3 units
Kamal purchases 80 articles for 11,180 and sells them at a loss equal to the selling price of 6 articles. What will be the selling price of 1 article?
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Answer: (A) 130
Explanation
Let the selling price of one article be SP.
The standard formula for loss is:
Loss = Total Cost Price - Total Selling Price
For 80 articles, this is expressed as:
Loss on 80 articles = CP of 80 articles - SP of 80 articles
We are given that the loss is equal to the selling price of 6 articles and the cost price of 80 articles is 11,180. Substituting these values into the equation:
6 × SP = 11,180 - 80 × SP
86 × SP = 11,180
SP = 11,180 / 86
SP = 130
380Quantitative Aptitude
If a + b + c = 10 and ab + bc + ca = 30 , then the value of a² +b² +c² is:
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Answer: (A) 40
Explanation
Using the standard algebraic identity:
(a + b + c)² = a² + b² + c² + 2(ab + bc + ca)
700 grams of cane sugar solution has 60% of sugar in it. How much sugar should be added to make it 75% in the solution?
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Answer: (D) 420 gm
Explanation
The initial solution of 700 grams contains 60% sugar, which is 420 grams of sugar and 280 grams of other components. To make the sugar concentration 75%, the 280 grams of other components must represent the remaining 25% of the new solution, meaning the new total weight of the solution is 1120 grams. The amount of sugar to be added is therefore 1120 grams minus the initial 700 grams, which equals 420 grams.
382Quantitative Aptitude
If the sum of two numbers is 25 and their product is 144, then what is the position difference between the two numbers?
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Answer: (B) 7
Explanation
The difference between two numbers x and y can be determined using the standard algebraic identity:
(x - y)² = (x + y)² - 4xy
Given that the sum of the two numbers (x + y) is 25 and their product (xy) is 144, substituting these values into the formula gives:
The positive difference between the two numbers is 7.
383Quantitative Aptitude
A can do a piece of work in 24 days and B can do it in 80 days. B works alone for 2 days and A works alone on the 3ʳᵈ day. This process continues till the work is completed. In how many days will the work be completed?
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Answer: (B) 45
Explanation
Let the total work be the Least Common Multiple (LCM) of the days taken by A and B, which is LCM(24, 80) = 240 units.
Efficiency of A = 240 ÷ 24 = 10 units per day.
Efficiency of B = 240 ÷ 80 = 3 units per day.
According to the given pattern, the work is done in cycles of 3 days:
Day 1: B works alone and does 3 units of work.
Day 2: B works alone and does 3 units of work.
Day 3: A works alone and does 10 units of work.
Total work done in one 3-day cycle = 3 + 3 + 10 = 16 units.
To complete the total work of 240 units, the number of such 3-day cycles required is:
240 ÷ 16 = 15 cycles.
Total days required to complete the work = 15 × 3 = 45 days.
384Quantitative Aptitude
The difference between the simple interest and compound interest on ₹1,000 for 1 year at 20% per annum, compounded half-yearly, is:
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Answer: (C) 10
Explanation
The difference between compound interest and simple interest for two conversion periods (half-years) can be calculated using the formula:
Difference = P × (r/100)²
Here, the principal P is ₹1,000.
The interest rate is 20% per annum, which becomes r = 10% per half-year.
The time of 1 year corresponds to 2 half-yearly compounding periods.
Find the volume of a hemisphere of radius 21 cm. (Use π = 22/7 )
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Answer: (A) 19404 cm³
Explanation
The volume of a hemisphere is given by the formula V = (2/3)πr³, where r is the radius of the hemisphere.
Substituting the given values of r = 21 cm and π = 22/7:
V = (2/3) × (22/7) × 21 × 21 × 21
Since the product of the denominators 3 × 7 equals 21, we can simplify the expression by canceling one 21 from the numerator:
V = 2 × 22 × 21 × 21
V = 44 × 441
V = 19404 cm³
386Quantitative Aptitude
Rakesh runs 4/3 times as fast as Mukesh. In a race, if Rakesh gives a lead of 60 m to Mukesh, find the distance from the starting point where both of them will meet.
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Answer: (B) 240 m
Explanation
The ratio of the speeds of Rakesh and Mukesh is 4 : 3.
Since distance is directly proportional to speed for a given duration, the ratio of the distances covered by Rakesh and Mukesh to the meeting point is also 4 : 3.
Let the distance covered by Rakesh be 4x and by Mukesh be 3x.
The difference in their distances is equal to the start lead given to Mukesh:
4x - 3x = 60 m
x = 60 m
The distance from the starting point where they meet is the total distance run by Rakesh:
4x = 4 × 60 m = 240 m
387Quantitative Aptitude
If x² = b - ax and x³(x³ + c) = d , then which of the following can be the values of c and d ?
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Answer: (C) c = a³ + 3ab and d = b³
Explanation
The given equation is x² = b - ax. Rearranging the terms, we get:
x² + ax = b
To find a relation involving x⁶ and x³, we cube both sides of this equation:
(x² + ax)³ = b³
Using the algebraic identity (p + q)³ = p³ + q³ + 3pq(p + q), where p = x² and q = ax, we expand the left side:
(x²)³ + (ax)³ + 3(x²)(ax)(x² + ax) = b³
x⁶ + a³x³ + 3ax³(x² + ax) = b³
Substitute b in place of x² + ax on the left side:
x⁶ + a³x³ + 3ax³(b) = b³
x⁶ + a³x³ + 3abx³ = b³
Factoring out x³:
x³(x³ + a³ + 3ab) = b³
Comparing this with the target equation x³(x³ + c) = d, we get:
c = a³ + 3ab
d = b³
388Quantitative Aptitude
A bike is purchased for ₹50,000. Its rate depreciates at 10% annually. In how many years will its value be ₹36,450?
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Answer: (A) 3
Explanation
The formula for the depreciated value of an asset over time is A = P(1 - R/100)ⁿ, where A is the depreciated value, P is the initial purchase price, R is the annual rate of depreciation, and n is the number of years.
Substituting the given values into the formula:
36450 = 50000(1 - 10/100)ⁿ
36450 = 50000(0.9)ⁿ
36450 / 50000 = (0.9)ⁿ
3645 / 5000 = (0.9)ⁿ
Dividing both the numerator and denominator by 5 on the left-hand side:
729 / 1000 = (0.9)ⁿ
(9/10)³ = (0.9)ⁿ
(0.9)³ = (0.9)ⁿ
Comparing the exponents, we get:
n = 3
389Quantitative Aptitude
If 2945÷ 19 - 11× 5 = 29 + a , find the value of a.
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Answer: (D) 71
Explanation
According to the BODMAS rule, division and multiplication are performed first.
First, perform the division:
2945 ÷ 19 = 155
Next, perform the multiplication:
11 × 5 = 55
Now, substitute these values into the given equation:
155 - 55 = 29 + a
100 = 29 + a
Solving for a:
a = 100 - 29
a = 71
390Quantitative Aptitude
If 15 kg of sugar cost 600, what is the cost of 25 kg of sugar?
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Answer: (C) 1,000
Explanation
By the unitary method, the cost of 1 kg of sugar is obtained by dividing the total cost of the initial quantity of sugar by that quantity:
Cost of 1 kg of sugar = 600 / 15 = 40
Using this unit price, the cost of 25 kg of sugar is calculated by multiplying the unit price by the desired quantity:
Cost of 25 kg of sugar = 25 × 40 = 1000
391Quantitative Aptitude
Nikhil suffers a loss of 140 when he sells a perfume at 20% discount. Find the marked price of the perfume if the cost price is 380.
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Answer: (B) 300
Explanation
The selling price of the perfume is calculated by subtracting the loss from the cost price:
A sphere passes through the eight corners of a cube of side 14 cm. Find the volume (in cm³ ) of the sphere. Take π = ²²⁄₇
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Answer: (A) 4312√3
Explanation
When a sphere passes through the eight corners of a cube, the sphere circumscribes the cube. Consequently, the diagonal of the cube is equal to the diameter of the sphere.
For a cube of side a = 14 cm, the length of its body diagonal is given by the formula:
d = a√3 = 14√3 cm
The radius r of the circumscribing sphere is half of the diagonal:
r = d / 2 = 7√3 cm
The volume V of a sphere is given by the formula:
V = (4/3) × π × r³
Substituting the values r = 7√3 cm and π = 22/7:
V = (4/3) × (22/7) × (7√3)³
V = (4/3) × (22/7) × 343 × 3√3
V = 4 × 22 × 49 × √3
V = 4312√3 cm³
393Quantitative Aptitude
If the height and slant height of a right circular cone are 8 cm and 10 cm, respectively, then the volume of the cone is (use π = ²²⁄₇ ): (correct to two decimal places)
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Answer: (B) 301.71 cm³
Explanation
The relationship between the slant height (l), height (h), and radius (r) of a right circular cone is given by the formula:
l² = r² + h²
Substituting the given values of slant height (l = 10 cm) and height (h = 8 cm):
10² = r² + 8²
100 = r² + 64
r² = 36
r = 6 cm
The volume (V) of a cone is given by the formula:
V = (1/3) × π × r² × h
Using the value of π as 22/7, substitute the radius and height into the formula:
V = (1/3) × (22/7) × 6² × 8
V = 12 × (22/7) × 8
V = 2112 / 7
V ≈ 301.71 cm³
394Quantitative Aptitude
A family spends £240 per month to buy sugar. A rise of 25% in the price of sugar compels the family to reduce the monthly consumption of sugar by 1.5 kg as it decides to spend the same amount of money on purchase of the commodity. What is the increased price per kg of sugar?
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Answer: (C) £40
Explanation
When the expenditure remains constant, the price and consumption are inversely proportional to each other.
An increase of 25% in the price of sugar means the price rises by a fraction of 1/4. To maintain the same expenditure, the consumption must decrease by a fraction of:
(1/4) / (1 + 1/4) = 1/5
Given that this reduction in consumption is 1.5 kg:
1/5 × Original Consumption = 1.5 kg
Original Consumption = 1.5 × 5 = 7.5 kg
Therefore, the new reduced consumption is:
New Consumption = 7.5 kg - 1.5 kg = 6 kg
The total money spent is £240. The increased price per kg of sugar is calculated by dividing the total expenditure by the new consumption:
Increased Price = 240 / 6 = £40 per kg
395Quantitative Aptitude
The table below gives the numbers of laptops of three different brands sold from four different multi-brands store in the city during a certain month.
| Stores | Dell | HP | Lenovo |
|---|---|---|---|
| A | 30 | 45 | 50 |
| B | 25 | 32 | 40 |
| C | 25 | 35 | 38 |
| D | 45 | 29 | 45 |
The number of Lenovo Laptop sold by stores A during the given month is approximately what percentage more than the number of Dell laptops sold by Store D during the same month?
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Answer: (C) 11.1
Explanation
The number of Lenovo laptops sold by Store A is 50.
The number of Dell laptops sold by Store D is 45.
To find the percentage by which the Lenovo laptops sold by Store A are more than the Dell laptops sold by Store D, the standard percentage increase formula is used:
Percentage More = ((Lenovo laptops sold by Store A - Dell laptops sold by Store D) / Dell laptops sold by Store D) × 100
In Class 8 of a school, the ratio of students playing cricket to those playing football is 27 : 13, while the ratio of those playing football to those playing hockey is 26 : 14. If the total number of students in Class 8 is 470, and each student plays exactly one game, find the percentage of students of the class playing cricket. [Give your answer correct to two decimal places.]
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Answer: (C) 57.45%
Explanation
To find the ratio of students playing cricket, football, and hockey, we combine the given individual ratios.
The ratio of cricket (C) to football (F) is 27 : 13.
The ratio of football (F) to hockey (H) is 26 : 14, which simplifies to 13 : 7.
Since the term representing football is 13 in both cases, the combined ratio of students playing the three games is:
C : F : H = 27 : 13 : 7
The sum of the ratio parts is:
27 + 13 + 7 = 47
Since each student plays exactly one game, the percentage of students playing cricket can be computed directly using their share of the total ratio parts:
Percentage of cricket players = (Cricket parts / Total parts) × 100
Percentage of cricket players = (27 / 47) × 100 = 2700 / 47 % ≈ 57.446%
Rounding to two decimal places, the percentage of students playing cricket is 57.45%.
399Quantitative Aptitude
The table below provides information about the marks obtained by a group of students in a test.
Marks | No. of Students
Less than 10 | 2
Less than 20 | 5
Less than 30 | 6
Less than 40 | 8
Less than 50 | 10
How many students scored at least 30 marks but less than 40 marks in the test?
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Answer: (D) 2
Explanation
The given data represents a cumulative frequency distribution of the less than type.
The number of students scoring less than 40 marks is 8.
The number of students scoring less than 30 marks is 6.
To find the number of students who scored at least 30 marks but less than 40 marks, which corresponds to the class interval 30-40, we subtract the cumulative frequency of students scoring less than 30 from the cumulative frequency of students scoring less than 40:
Number of students = 8 - 6 = 2
400Quantitative Aptitude
If sec θ - cos θ = 14 and 14sec θ = x then the value of x is
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Answer: (A) tan²θ
Explanation
The first given equation is sec θ - cos θ = 14.
We are given that x = 14 sec θ.
Substituting the value of 14 from the first equation into the second equation:
x = (sec θ - cos θ) sec θ
Multiplying the terms:
x = sec²θ - sec θ cos θ
Since sec θ cos θ = 1:
x = sec²θ - 1
Using the trigonometric identity sec²θ - tan²θ = 1, we get:
x = tan²θ