A hemispherical bowl has internal radius of 6 cm. The internal surface area would be: (takeπ - 3.14)
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Answer: (D) 226.08cm²
Explanation
The internal surface area of a hemispherical bowl is given by the formula for the curved surface area of a hemisphere:
A = 2πr²
Here, the internal radius r is 6 cm and π is taken as 3.14.
Substituting these values into the formula:
A = 2 × 3.14 × 6²
A = 2 × 3.14 × 36
A = 72 × 3.14
A = 226.08 cm²
52Quantitative Aptitude
A train 156 m long passes a km stone in 30 seconds and another train of the same length travelling in opposite direction in 10 seconds. The speed of the second train is
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Answer: (A) 93.6ᵏᵐ⁄ₕᵣ
Explanation
The speed of the first train (v1) is calculated by dividing the length of the train by the time it takes to pass a stationary km stone:
v1 = 156 / 30 = 5.2 m/s
When two trains of equal length cross each other in opposite directions, their relative speed is the sum of their individual speeds (v1 + v2), and the total distance covered is the sum of their lengths:
Total distance = 156 + 156 = 312 m
Using the relative speed relation, relative speed = total distance / time:
v1 + v2 = 312 / 10
5.2 + v2 = 31.2
v2 = 26 m/s
To convert the speed of the second train from m/s to km/hr, multiply by 18/5:
Speed of the second train = 26 × 18/5 = 93.6 km/hr
53Quantitative Aptitude
If water is freezed to become ice, its volume is increased by 10% , then if the ice is melted to water again, its volume will be decreased by:
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Answer: (D) ⁹⁄₁₁%
Explanation
Let the initial volume of water be 100 units.
When water freezes to ice, its volume increases by 10%:
Volume of ice = 100 + 10 = 110 units
When this ice melts back into water, its volume decreases from 110 units to its original volume of 100 units.
Decrease in volume = 110 - 100 = 10 units
The percentage decrease in volume is calculated relative to the volume of ice:
Percentage decrease = (Decrease in volume / Volume of ice) × 100
Percentage decrease = (10 / 110) × 100 = 100/11 % = 9 1/11 %
54Quantitative Aptitude
The simplified value of following is:
(³⁄₁₅ a⁵ b⁶ c³ × ⁵⁄₉ a b⁵ c⁴) ÷ ¹⁰⁄₂₇ a² b c³
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Answer: (C) ³⁄₁₀ a⁴ b¹⁰ c⁴
Explanation
To simplify the given expression, first perform the multiplication inside the parentheses:
Divide the corresponding variable terms by subtracting their exponents:
a⁶ ÷ a² = a⁶⁻² = a⁴
b¹¹ ÷ b = b¹¹⁻¹ = b¹⁰
c⁷ ÷ c³ = c⁷⁻³ = c⁴
Combining these parts gives the simplified expression:
3/10 a⁴ b¹⁰ c⁴
55Quantitative Aptitude
A number of boys raised ₹12,544 for a famine fund, each boy has given as many rupees as there were boys. The number of boys was:
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Answer: (C) 112
Explanation
Let the number of boys be x. Since each boy contributed as many rupees as there were boys, the contribution of each boy is ₹x.
The total amount raised is:
Total Amount = x × x = x²
We are given that the total amount raised is ₹12,544:
x² = 12544
x = √12544
We can find the square root by estimating the range. Since 110² = 12100 and 120² = 14400, the value of x must lie between 110 and 120. Since the units digit of 12544 is 4, the square root must end in either 2 or 8. Within this range, the only matching value is 112.
Verifying this:
112 × 112 = 12544
56Quantitative Aptitude
The value of X in the equation tan² tan²(π)/(4) - C o s²(π)/(3) - X S i n(π)/(4)C o s(π)/(4)T a n(π)/(3) is:
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Answer: (A) (√3)/(2)
Explanation
The given equation is tan²(π/4) - cos²(π/3) - X sin(π/4) cos(π/4) tan(π/3) = 0.
Substitute the standard values of the trigonometric functions:
tan(π/4) = 1
cos(π/3) = ½
sin(π/4) = 1/√2
cos(π/4) = 1/√2
tan(π/3) = √3
Substituting these values into the equation:
1² - (½)² - X × (1/√2) × (1/√2) × √3 = 0
1 - ¼ - X × ½ × √3 = 0
¾ - (√3 / 2) X = 0
(√3 / 2) X = ¾
X = (¾) × (2 / √3)
X = √3 / 2
57Quantitative Aptitude
ABCD is a square. Draw a triangle QBC on side BC considering BC as base and draw a triangle PAC on AC as its base such that △ QBC ∼ △ PAC , Then (Area of △ QBC)/(Area of △ PAC) is equal to:
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Answer: (C) 1/2
Explanation
Let the side of the square ABCD be a. The diagonal AC of the square acts as the hypotenuse of the right-angled triangle ABC, which is given by Pythagoras theorem:
AC = √(a² + a²) = a√2
According to the properties of similar triangles, the ratio of the areas of two similar triangles is equal to the ratio of the squares of their corresponding sides. Since triangle QBC is similar to triangle PAC:
Area of ΔQBC / Area of ΔPAC = (BC / AC)²
Substituting the values BC = a and AC = a√2 into the formula:
Area of ΔQBC / Area of ΔPAC = (a / a√2)² = (1 / √2)² = 1/2
58Quantitative Aptitude
The current ages of Sonali and Monali are in the ratio 5 : 3 Five years from now, their ages will be in the ratio 10 : 7 Then, Monali's current age is
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Answer: (A) 9 years
Explanation
Let the current ages of Sonali and Monali be 5x and 3x, respectively.
Five years from now, their ages will be 5x + 5 and 3x + 5.
According to the given condition:
(5x + 5) / (3x + 5) = 10 / 7
The formula for the total accumulated amount (A) under compound interest is:
A = P × (1 + r/100)ⁿ
Substituting the given values:
A = 12000 × (1 + 5/100)³
A = 12000 × (1.05)³
A = 12000 × 1.157625
A = 13891.50
The compound interest (CI) is calculated by subtracting the principal from the total amount:
CI = A - P
CI = 13891.50 - 12000 = 1891.50
60Quantitative Aptitude
Value of the expression: (1 + 2 sin 60° cos 60°)/(sin 60° + cos 60°) + (1 - 2 sin 60° cos 60°)/(sin 60° - cos 60°)
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Answer: (C) √3
Explanation
Using the trigonometric identity sin²θ + cos²θ = 1, the given expression can be simplified by replacing 1 in the numerators.
For any angle θ, we have:
1 + 2 sin θ cos θ = sin²θ + cos²θ + 2 sin θ cos θ = (sin θ + cos θ)²
1 - 2 sin θ cos θ = sin²θ + cos²θ - 2 sin θ cos θ = (sin θ - cos θ)²
Substituting these identities into the expression gives:
(sin 60° + cos 60°² / (sin 60° + cos 60°) + (sin 60° - cos 60°² / (sin 60° - cos 60°)
This simplifies directly to:
(sin 60° + cos 60°) + (sin 60° - cos 60°) = 2 sin 60°
Since sin 60° = √3/2, substituting this value yields:
2 × (√3/2) = √3
61Quantitative Aptitude
If (sinθ + cosθ)/(sinθ - cosθ) = 3 then the value of sin⁴θ is:
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Answer: (A) 4/5
Explanation
Starting from sinθ + cosθ = 3(sinθ − cosθ), collect terms to get 2sinθ = 4cosθ, so sinθ = 2cosθ. Since cosθ = √(1 − sin²θ), squaring gives sin²θ = 4(1 − sin²θ), so 5sin²θ = 4 and sin²θ = 4/5, which is the value asked for.
62Quantitative Aptitude
If Sin 2θ = (√3)/(2) then the value of sin 3θ is:
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Answer: (C) 1
Explanation
Given the equation sin 2θ = √3/2, we know from standard trigonometric values that sin 60° = √3/2. By equating the angles, we get 2θ = 60°, which simplifies to θ = 30°.
Substituting this value of θ into the expression sin 3θ gives sin(3 × 30°) = sin 90°. Since the standard value of sin 90° is 1, the value of sin 3θ is 1.
63Quantitative Aptitude
The volume of the largest right circular cone that can be cut out of a cube of edge 7cm? ( Use π = ²²⁄₇ ).
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Answer: (D) 89.8cm³
Explanation
The volume of the largest right circular cone that can be carved out of a cube of edge a is obtained when the base of the cone is inscribed in one of the faces of the cube and its height is equal to the edge of the cube.
Therefore, the dimensions of the cone are:
Radius, r = a/2 = 7/2 cm
Height, h = a = 7 cm
The volume V of a cone is given by the formula:
V = 1/3 × π × r² × h
Substituting the given values:
V = 1/3 × 22/7 × (7/2)² × 7
V = 1/3 × 22/7 × 49/4 × 7
V = 539/6
V ≈ 89.8 cm³
64Quantitative Aptitude
Two positive whole numbers are such that the sum of the first and twice the second number is 8 and their difference is 2. The numbers are:
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Answer: (D) 4,2
Explanation
Let the first number be x and the second number be y. According to the given conditions, we can set up the following system of linear equations:
x + 2y = 8
x - y = 2
To find the values of x and y, subtract the second equation from the first:
(x + 2y) - (x - y) = 8 - 2
3y = 6
y = 2
Substitute the value of y into the second equation:
x - 2 = 2
x = 4
Thus, the first number is 4 and the second number is 2, both of which are positive whole numbers that satisfy the given conditions.
65Quantitative Aptitude
The speed of a car in 54ᵏᵐ⁄ₕᵣ . What is its speed in (m)/(sec) ?
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Answer: (D) 15(m)/(sec)
Explanation
To convert speed from kilometers per hour (km/hr) to meters per second (m/sec), multiply the given value by 5/18. This conversion factor is derived from converting 1 kilometer to 1000 meters and 1 hour to 3600 seconds, which simplifies to 1000/3600 = 5/18.
Speed in m/sec = 54 × 5/18 = 3 × 5 = 15 m/sec
66Quantitative Aptitude
The income of a company increase 20% per annum. If its income ¥ 26,64,000 in the year 2012, then its income in the year 2010 was:
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Answer: (C) 18,50,000
Explanation
The relation between the incomes of two different years under a constant compound annual growth rate is given by the formula:
Income in 2012 = Income in 2010 × (1 + r/100)ⁿ
Here, the annual growth rate r = 20% and the time period n = 2 years (from 2010 to 2012).
Substituting the given values into the formula:
26,64,000 = Income in 2010 × (1 + 20/100)²
26,64,000 = Income in 2010 × (1.2)²
26,64,000 = Income in 2010 × 1.44
Income in 2010 = 26,64,000 ÷ 1.44
Income in 2010 = 18,50,000
67Quantitative Aptitude
The distance between centers of two circles of radii 3cm and 8cm is 13cm . If the points of contact of a direct common tangent to the circles are P and Q, the length of the line segment PQ is:
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Answer: (C) 12 cm
Explanation
The formula for the length of a direct common tangent to two circles with radii r₁ and r₂ and distance between their centers d is given by:
PQ = √(d² - (r₂ - r₁)²)
Substituting the given values, where d = 13 cm, r₁ = 3 cm, and r₂ = 8 cm:
A shopkeeper marks his goods 20% higher than the cost price and allows a discount of 5% . The percentage of his profit is.
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Answer: (A) 14%
Explanation
Let the Cost Price be ₹100. Since the goods are marked 20% higher than the cost price, the Marked Price is:
Marked Price = 100 × (1 + 20/100) = ₹120
A discount of 5% is allowed on the Marked Price, so the Selling Price is:
Selling Price = 120 × (1 - 5/100) = 120 × 0.95 = ₹114
The profit percentage is calculated using the formula:
Profit % = ((Selling Price - Cost Price) / Cost Price) × 100
Profit % = ((114 - 100) / 100) × 100 = 14%
Alternatively, applying the successive percentage formula where a is the markup percentage (+20%) and b is the discount percentage (-5%):
Net profit % = a + b + ab/100
Net profit % = 20 - 5 + (20 × (-5))/100 = 15 - 1 = 14%
69Quantitative Aptitude
In △ ABC, AB = BC = K, AC = √2 K , then △ ABC is a:
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Answer: (D) Right isosceles triangle
Explanation
Since AB = BC = K, the triangle has two equal sides, making it an isosceles triangle.
Applying the Pythagorean theorem to check the relationship between the sides:
AB² + BC² = K² + K² = 2K²
Also:
AC² = (√2 K)² = 2K²
Since AB² + BC² = AC², the converse of the Pythagorean theorem holds true, proving that the triangle has a right angle at vertex B. Therefore, the triangle is both right-angled and isosceles, making it a right isosceles triangle.
70Quantitative Aptitude
The smallest five digit number which is divisible by 12, 18 and 21 is:
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Answer: (D) 10080
Explanation
To find the smallest five-digit number divisible by 12, 18, and 21, we first find the Least Common Multiple (LCM) of the given numbers.
The prime factorizations of the numbers are 12 = 2² × 3, 18 = 2 × 3², and 21 = 3 × 7.
LCM(12, 18, 21) = 2² × 3² × 7 = 252
The smallest five-digit number is 10000. Dividing 10000 by 252 yields 39 with a remainder of 172. To find the smallest five-digit multiple of 252, we multiply 252 by the next higher integer, 40:
252 × 40 = 10080
71Quantitative Aptitude
By selling an article for 450. I lose 20% . For what amount should I sell it to gain 20% ?
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Answer: (D) 675
Explanation
Using the direct proportional relation between selling prices under different profit or loss percentages:
New Selling Price = 450 × (100 + 20) / (100 - 20)
New Selling Price = 450 × 120 / 80
New Selling Price = 450 × 3/2
New Selling Price = 675
This directly yields the required selling price to achieve a 20% gain.
72Quantitative Aptitude
In an exam the sum of the scores of A and B is 120, that of B and C is 130 and that of C and A is 140. Then the score of C is
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Answer: (D) 75
Explanation
Summing the three given equations:
A + B = 120
B + C = 130
C + A = 140
We get:
2(A + B + C) = 120 + 130 + 140
2(A + B + C) = 390
A + B + C = 195
To find the score of C, substitute the value of A + B from the first equation into this combined equation:
120 + C = 195
C = 195 - 120
C = 75
73Quantitative Aptitude
If α + β = 90° then the expression (tan α)/(tan β) + sin² α + sin² β is equal to:
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Answer: (C) Sec²α
Explanation
Since α + β = 90°, we have β = 90° - α.
From trigonometric complementary angle identities, we know:
tan β = tan(90° - α) = cot α
sin β = sin(90° - α) = cos α
Substituting these into the given expression:
(tan α / tan β) + sin² α + sin² β = (tan α / cot α) + sin² α + cos² α
Since cot α = 1/tan α and sin² α + cos² α = 1, the expression simplifies to:
tan² α + 1
Using the standard identity 1 + tan² α = sec² α, we obtain sec² α.
74Quantitative Aptitude
Two circles of radii 5 cm and 3 cm touch extenally, then the ratio in which the direct common tangent to the circles divides extenally the line joining the centers of the circles is:
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Answer: (D) 5:3
Explanation
The point of intersection of the direct common tangent with the line joining the centers of two circles is known as the external center of similitude. According to the property of circles, this point divides the line segment joining the centers of the circles externally in the ratio of their respective radii.
Let the radii of the two circles be r₁ and r₂. Here, r₁ = 5 cm and r₂ = 3 cm. Therefore, the ratio in which the direct common tangent divides the line joining the centers externally is r₁ : r₂, which equals 5 : 3.
75Quantitative Aptitude
A fruit seller buys oranges at the rate of ₹10 per dozen and sells at the rate of ₹12 per dozen. His gain percent is
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Answer: (B) 20%
Explanation
The cost price of one dozen oranges is ₹10 and the selling price of one dozen oranges is ₹12.
The formula for gain is:
Gain = Selling Price - Cost Price
Gain = 12 - 10 = ₹2
The formula for gain percent is:
Gain % = (Gain / Cost Price) × 100
Substituting the values into the formula:
Gain % = (2 / 10) × 100 = 20%
76Quantitative Aptitude
The outer circumference of a circular race track is 528 metre. The track is every where 14 metre wide. Cost of levelling the track at the rate of ₹10 per sq. metre is:
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Answer: (D) 67760
Explanation
Outer circumference of the circular track = 2πR = 528 m, where R is the outer radius.
Using π = 22/7:
2 × (22/7) × R = 528
R = (528 × 7) / 44
R = 84 m
Since the track is 14 m wide everywhere, the inner radius r is:
r = R - 14 = 84 - 14 = 70 m
The area of the track is the difference between the outer and inner circular areas:
Area = π(R² - r²) = π(R - r)(R + r)
Area = (22/7) × (84 - 70) × (84 + 70)
Area = (22/7) × 14 × 154
Area = 44 × 154 = 6776 sq. m
The cost of levelling the track at the rate of ₹10 per sq. m is:
Cost = 6776 × 10 = ₹67760
77Quantitative Aptitude
If 1³ + 2³ + … … 10³ = 3025 , then the value of 2³ + 4³ + … … + 20³ is:
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Answer: (C) 24200
Explanation
The given series is:
S = 2³ + 4³ + ... + 20³
This can be rewritten by factoring out 2³ from each term:
S = (2 × 1)³ + (2 × 2)³ + ... + (2 × 10)³
S = 2³(1³ + 2³ + ... + 10³)
Substituting the given value of 1³ + 2³ + ... + 10³ = 3025:
S = 8 × 3025
S = 24200
78Quantitative Aptitude
The surface are of sphere is 616cm² . The volume of the sphere would be:
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Answer: (C) 1437⅓ cm²
Explanation
The surface area of a sphere is given by the formula 4πr², where r is the radius of the sphere.
Using the given surface area:
4πr² = 616
4 × (22/7) × r² = 616
88/7 × r² = 616
r² = (616 × 7) / 88
r² = 7 × 7 = 49
r = 7 cm
The volume of a sphere is given by the formula 4/3 πr³.
Substituting r = 7 cm into the volume formula:
Volume = 4/3 × (22/7) × 7³
Volume = 4/3 × 22 × 49
Volume = 4312 / 3
Volume = 1437 ⅓ cm³
79Quantitative Aptitude
A vessel contains 60 litres of milk. 12 litres of milk taken out from it and replaced by water. Then again from mixture. 12 litres are again taken out and replaced by water. The ratio of milk and water in the resultant mixture is:
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Answer: (D) 16:9
Explanation
The remaining quantity of milk after n replacement operations is given by the formula:
Remaining milk = Initial quantity × (1 - Quantity replaced / Initial quantity)ⁿ
Here, the initial quantity of milk is 60 litres, the quantity replaced each time is 12 litres, and the operation is performed n = 2 times.
Since the total volume of the mixture remains 60 litres, the quantity of water in the final mixture is:
Water = 60 - 38.4 = 21.6 litres
The ratio of milk and water in the resultant mixture is:
Milk : Water = 38.4 : 21.6
Milk : Water = 384 : 216
Dividing both terms by 24 gives the simplified ratio of 16:9.
80Quantitative Aptitude
If (2a - 1)² +(4b - 3)² +(4c + 5)² = 0, Then the value of (a³ + b³ + c³ - 3abc)/(a² + b² + c²) is:
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Answer: (D) 0
Explanation
The given equation is:
(2a - 1)² + (4b - 3)² + (4c + 5)² = 0
Since the sum of squares of real numbers is always non-negative, the sum can only be zero if each individual term is zero. This gives:
2a - 1 = 0 which means a = ½
4b - 3 = 0 which means b = ¾
4c + 5 = 0 which means c = -5/4
Adding the values of a, b, and c gives:
a + b + c = 2/4 + 3/4 - 5/4 = 0
We use the algebraic identity:
a³ + b³ + c³ - 3abc = (a + b + c)(a² + b² + c² - ab - bc - ca)
Since a + b + c = 0, the numerator becomes:
a³ + b³ + c³ - 3abc = 0 × (a² + b² + c² - ab - bc - ca) = 0
Since a² + b² + c² is a positive non-zero quantity, dividing the numerator by this term yields:
(a³ + b³ + c³ - 3abc) / (a² + b² + c²) = 0
81Quantitative Aptitude
A house was sold for ¥ 123,456 by giving a discount of x% then the list price was:
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Answer: (A) (100y)/(100 - x)
Explanation
Let the list price of the house be LP. The selling price is given as y, and the discount rate is x%.
The formula relating the selling price, list price, and discount percentage is:
Selling Price = List Price × (1 - Discount/100)
Substituting the given values into this relation:
y = LP × (1 - x/100)
y = LP × ((100 - x)/100)
Rearranging the terms to solve for the list price:
LP = 100y / (100 - x)
82Quantitative Aptitude
If a + (1)/(b) - 1 and b + (1)/(c) - 1 , then c + ¹⁄ₐ is equal to:
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Answer: (B) 1
Explanation
From the first given equation, we have:
a + 1/b = 1
a = (b - 1)/b
1/a = b/(b - 1)
From the second given equation, we have:
b + 1/c = 1
1/c = 1 - b
c = 1/(1 - b) = -1/(b - 1)
Adding the expressions for c and 1/a:
c + 1/a = -1/(b - 1) + b/(b - 1)
c + 1/a = (b - 1)/(b - 1)
c + 1/a = 1
Alternatively, assuming a convenient value like b = 2:
a + 1/2 = 1, which means a = 1/2
2 + 1/c = 1, which means c = -1
Substituting these values:
c + 1/a = -1 + 1/(1/2) = -1 + 2 = 1
83Quantitative Aptitude
If 20 women can lay a road of length 100 m in 10 days. 10 women can lay the same road of length 50m in:
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Answer: (B) 10 days
Explanation
Using the work equivalence formula:
(M₁ × D₁) / W₁ = (M₂ × D₂) / W₂
where M is the number of women, D is the number of days, and W is the work done (length of the road).
Substituting the given values:
M₁ = 20, D₁ = 10, W₁ = 100
M₂ = 10, W₂ = 50
We get:
(20 × 10) / 100 = (10 × D₂) / 50
Simplifying the equation:
2 = D₂ / 5
D₂ = 10
84Quantitative Aptitude
83⅓% of π 90 is equal to 60% of ?
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Answer: (B) 125
Explanation
Convert the percentage 83 1/3% into a fraction:
83 1/3% = 250/3% = (250 / 3) × (1 / 100) = 5/6
Now, calculate 83 1/3% of 90:
5/6 × 90 = 75
Let the required number be x. According to the question, 60% of x is equal to 75:
60% × x = 75
3/5 × x = 75
x = 75 × 5/3
x = 25 × 5
x = 125
85Quantitative Aptitude
A milkman mixed the water with milk to gain 25% by selling the mixture at cost price. The ratio of water and milk is:
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Answer: (B) 1:4
Explanation
Since the mixture is sold at the cost price of pure milk, the profit is solely due to the addition of free water. The relationship between the profit percentage, water, and milk is given by:
Profit % = (Volume of water / Volume of milk) × 100
Given a profit of 25%:
25 = (Volume of water / Volume of milk) × 100
Volume of water / Volume of milk = 25 / 100 = 1 / 4
This yields a ratio of water to milk of 1:4.
86Quantitative Aptitude
If x - ¹⁄ₓ = 2 , then the value of following is: x³ - (1)/(x³) = ?
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Answer: (B) 14
Explanation
Using the algebraic identity (x - 1/x)³ = x³ - 1/x³ - 3(x - 1/x), we substitute the given value of x - 1/x = 2. This gives 2³ = x³ - 1/x³ - 3(2), which simplifies to 8 = x³ - 1/x³ - 6, and thus x³ - 1/x³ = 14.
87Quantitative Aptitude
Percentage of students who are not members of any club is:
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Answer: (D) 5%
Explanation
Based on the pie chart, the percentage distribution of students who are members of the clubs is:
Members of both clubs = 75%
Members of football club only = 15%
Members of cricket club only = 5%
To find the percentage of students who are not members of any club, we first calculate the total percentage of students who are members of at least one club:
75% + 15% + 5% = 95%
Subtracting this from the total student population of 100% gives:
100% - 95% = 5%
88Quantitative Aptitude
The total surface area of a right circular cylinder with radius of the base 7 cm and height 20 cm is:
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Answer: (A) 1188cm²
Explanation
The total surface area of a right circular cylinder is given by the formula:
Total Surface Area = 2πr(h + r)
where r is the radius of the base and h is the height of the cylinder.
Substituting the given values, r = 7 cm, h = 20 cm, and taking π ≈ 22/7:
Total Surface Area = 2 × (22/7) × 7 × (20 + 7)
Total Surface Area = 2 × 22 × 27
Total Surface Area = 44 × 27
Total Surface Area = 1188 cm²
89Quantitative Aptitude
A car goes 20 metres in a second. Find its speed in Km/hr
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Answer: (B) 72
Explanation
To convert speed from metres per second (m/s) to kilometres per hour (km/h), multiply the speed value by 18/5.
Given that the car travels 20 metres in one second, its speed is 20 m/s.
Using the conversion formula:
Speed in km/h = 20 × 18/5 = 4 × 18 = 72 km/h.
90Quantitative Aptitude
The area of circle whose radius is the diagonal of a square whose area is 4 is:
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Answer: (D) 8π
Explanation
Let the side of the square be s. The area of the square is s² = 4, which gives s = 2.
The diagonal of a square is given by d = s√2. Substituting s = 2, the diagonal is d = 2√2.
The radius r of the circle is equal to this diagonal, so r = 2√2.
The area of the circle is calculated using the formula A = πr². Substituting r = 2√2 yields A = π × (2√2)² = 8π.
91Quantitative Aptitude
An article is sold a profit of 25% . If the selling price is doubled, the profit will be:
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Answer: (D) 150%
Explanation
Let the cost price of the article be ₹100. Since the article is sold at a profit of 25%, the initial selling price is ₹125.
When the selling price is doubled, the new selling price becomes 2 × ₹125 = ₹250.
With the cost price remaining at ₹100, the new profit earned is ₹250 - ₹100 = ₹150.
The new profit percentage is calculated as (New Profit / Cost Price) × 100, which gives (150 / 100) × 100 = 150%.
92Quantitative Aptitude
The sum of two numbers is 37 and the difference of their squares is 185, then the difference of the two numbers is
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Answer: (A) 5
Explanation
Using the algebraic identity for the difference of squares:
x² - y² = (x + y)(x - y)
Let the two numbers be x and y. We are given:
x + y = 37
x² - y² = 185
Substituting these values into the formula:
185 = 37 × (x - y)
Solving for the difference of the two numbers (x - y):
x - y = 185 / 37 = 5
93Quantitative Aptitude
A, B and C can complete a work in 10, 12 and 15 days respectively. A left the work 5 days before the work was completed and B left 2 days after A had left. Number of days required to complete the whole work are:
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Answer: (D) 7
Explanation
Let the total work be the Least Common Multiple of the individual days taken by A, B, and C, which is the LCM of 10, 12, and 15, representing 60 units of work.
The work efficiencies per day for each person are:
Efficiency of A = 60 ÷ 10 = 6 units
Efficiency of B = 60 ÷ 12 = 5 units
Efficiency of C = 60 ÷ 15 = 4 units
Let the total number of days taken to complete the entire work be x.
A left 5 days before completion, meaning A worked for (x - 5) days.
B left 2 days after A, meaning B worked for (x - 5 + 2) = (x - 3) days.
C worked for the entire duration of x days.
We can set up the equation for the total work done:
6 × (x - 5) + 5 × (x - 3) + 4 × x = 60
6x - 30 + 5x - 15 + 4x = 60
15x - 45 = 60
15x = 105
x = 7
94Quantitative Aptitude
A rectangular carpet has an area of 120m² and a perimeter of 46 meter. The length of its diagonal is:
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Answer: (D) 17 metre
Explanation
Let the length and width of the rectangular carpet be l and w respectively.
The perimeter of the carpet is given by the formula:
2(l + w) = 46
l + w = 23
The area of the carpet is:
l × w = 120
The length of the diagonal d is related to the sides by the Pythagorean theorem:
d² = l² + w²
Using the algebraic identity (l + w)² = l² + w² + 2lw, we can substitute the known values:
23² = d² + 2(120)
529 = d² + 240
d² = 529 - 240
d² = 289
d = √289 = 17
95Quantitative Aptitude
If 4Sin²θ - 1 = 0 and angle θ is less than 90° . Then the value of Cos²θ +tan²θ is: Take (0⁰ < θ < 90⁰)
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Answer: (B) ¹³⁄₁₂
Explanation
Given the equation:
4 sin²θ - 1 = 0
We can solve for sin²θ:
4 sin²θ = 1
sin²θ = 1/4
Since the angle θ is in the first quadrant (0° < θ < 90°), sin θ must be positive:
sin θ = 1/2
This corresponds to:
θ = 30°
Now, we substitute θ = 30° into the expression cos²θ + tan²θ:
cos 30° = √3/2
cos² 30° = (√3/2)² = 3/4
tan 30° = 1/I√3
tan² 30° = (1/√3)² = 1/3
Adding these two values together:
cos² 30° + tan² 30° = 3/4 + 1/3
To add these fractions, we find a common denominator, which is 12:
(3 × 3)/12 + (1 × 4)/12 = 9/12 + 4/12 = 13/12
96Quantitative Aptitude
The radius of base and curved surface area of a right cylinder is 'r' units and 4π rh square units respectively. The height of the cylinder is:
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Answer: (A) 2h units
Explanation
The formula for the curved surface area of a right circular cylinder of radius r and height H is given by 2πrH.
Equating this standard formula to the given curved surface area of 4πrh:
2πrH = 4πrh
Dividing both sides by 2πr:
H = 2h
Thus, the height of the cylinder is 2h units.
97Quantitative Aptitude
Out of 10 teachers of a school, one teacher retires and in place of him a new teacher 25 yrs of old joins. As a result of it average age of the teachers reduces by 3 years. Age of the retired teacher (in year) is:
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Answer: (A) 55
Explanation
Let R be the age of the retired teacher, N be the age of the new teacher, and n be the total number of teachers.
The relationship between the change in average age and the ages of the replaced and new members is given by the formula:
Change in average = (N - R) / n
Here, the number of teachers (n) is 10, the age of the new teacher (N) is 25, and the average age reduces by 3 years, which represents a change of -3.
Substituting these values into the relation:
-3 = (25 - R) / 10
-30 = 25 - R
R = 25 + 30
R = 55
The age of the retired teacher is 55 years.
98Quantitative Aptitude
The marked price is 10% higher than the cost price. A discount of 10% is given on the marked price. In this kind of sale, the seller
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Answer: (D) loses 1%
Explanation
Using the successive percentage change formula, the net profit or loss percentage when a price is increased by a% and then decreased by b% is given by:
Net percentage change = a - b - ab/100
Here, the cost price is increased by 10% to set the marked price (a = 10), and a discount of 10% is given on the marked price (b = 10).
A train passes two bridges of lengths 500m and 250m in 100 seconds and 60 seconds respectively. The length of the train is:
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Answer: (B) 125 m
Explanation
Let L be the length of the train and v be its speed. When a train crosses a bridge, the total distance traveled is the sum of the length of the train and the length of the bridge.
For the first bridge of length 500 m, the train takes 100 seconds:
L + 500 = 100v
For the second bridge of length 250 m, the train takes 60 seconds:
L + 250 = 60v
Subtracting the second equation from the first equation:
(L + 500) - (L + 250) = 100v - 60v
250 = 40v
v = 25/4 m/s
Substituting the value of v into the second equation:
L + 250 = 60 × (25/4)
L + 250 = 15 × 25
L + 250 = 375
L = 125 m
100Quantitative Aptitude
The amount on ₹ 25000 in 2 years at annually compound interest, if the rates for the successive years be 4% and 5% per annum respectively is:
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Answer: (C) 27300
Explanation
The formula for the total amount A at the end of 2 years with successive annual compound interest rates r₁ and r₂ is:
A = P × (1 + r₁/100) × (1 + r₂/100)
Given:
P = ₹ 25000
r₁ = 4%
r₂ = 5%
Substituting these values into the formula:
A = 25000 × (1 + 4/100) × (1 + 5/100)
A = 25000 × (104/100) × (105/100)
A = 250 × 1.04 × 105
A = 260 × 105
A = 27300