SSC CHSL Tier 1 2021 General Intelligence & Reasoning Questions with Solutions

Explanation

The series follows an alternating pattern where each successive term is obtained by multiplying the previous term by 2 and then alternatively adding 4 or subtracting 3:

6 × 2 + 4 = 16 16 × 2 - 3 = 29 29 × 2 + 4 = 62 62 × 2 - 3 = 121 121 × 2 + 4 = 246

Explanation

The given series follows an alternating pattern of multiplication and addition using consecutive natural numbers starting from 2.

The step-by-step pattern is: 15 × 2 = 30 30 + 3 = 33 33 × 4 = 132 132 + 5 = 137 137 × 6 = 822

Applying this sequence of operations, the missing number is obtained by multiplying the third term by 4, giving 33 × 4 = 132. This is verified by the next step, where adding 5 to 132 correctly results in 137.

Explanation

In the given number pairs, the second number is obtained by arranging the digits of the first number in descending order. For the pair 4612 - 6412, arranging the digits of 4612 in descending order yields 6421, which is different from the given second number 6412. This deviation makes it the odd pair.

Explanation

The numbers in each row follow a pattern where the third number is obtained by multiplying the first number by 8.

First row: 8 × 9 = 72

Second row: 8 × 7 = 56

Third row: 8 × 23 = 184

Explanation

In each row of the given pattern, the second number is three times the first number, and the third number is five times the first number.

For the first row: 12 × 3 = 36 12 × 5 = 60

For the second row: 24 × 3 = 72 24 × 5 = 120

Following the same logic for the third row: 33 × 3 = 99 33 × 5 = 165

Explanation

When the letters b c d b b d are sequentially placed in the blanks, the completed letter series is:

d b c d c b d d b c d c b d d b c d c b d

This sequence is formed by the continuous repetition of a 7-letter block:

d b c d c b d

Dividing the completed series into segments of 7 letters clearly shows this repeating pattern:

d b c d c b d - d b c d c b d - d b c d c b d

Explanation

To arrange the words in alphabetical order as they would appear in an English dictionary, we compare their letters from left to right. All five words begin with the letters Ma. Comparing their third letters, we have l in Malfunction (2), n in Manageable (5) and Manipulation (4), s in Masterpiece (3), and t in Mathematic (1). Since l comes first alphabetically, Malfunction (2) is placed first. For the two words starting with Man, we compare their fourth letters: a in Manageable (5) comes before i in Manipulation (4), which puts Manageable (5) second and Manipulation (4) third. Finally, comparing Masterpiece (3) and Mathematic (1), the letter s comes before t, making Masterpiece (3) fourth and Mathematic (1) fifth.

Explanation

The given series is an alternating series consisting of two separate sequences for the odd-positioned and even-positioned terms.

For the odd-positioned terms (1st, 3rd, 5th, and 7th terms), the numbers increase by consecutive cubes: 1st term = 74 3rd term = 74 + 2³ = 74 + 8 = 82 5th term = 82 + 3³ = 82 + 27 = 109 7th term = 109 + 4³ = 109 + 64 = 173

For the even-positioned terms (2nd, 4th, 6th, and 8th terms), the numbers increase by consecutive fourth powers: 2nd term = 62 4th term = 62 + 2⁴ = 62 + 16 = 78 6th term = 78 + 3⁴ = 78 + 81 = 159 8th term (?) = 159 + 4⁴ = 159 + 256 = 415

The question mark is at the 8th position, which follows the even-positioned pattern: 159 + 256 = 415

Explanation

The relationship among the numbers in each set follows the pattern: (First number × 5) - (Second number)² = Third number

For the first set (18, 5, 65): (18 × 5) - 5² = 90 - 25 = 65

For the second set (14, 3, 61): (14 × 5) - 3² = 70 - 9 = 61

Applying the same mathematical pattern to the set (25, 11, 4): (25 × 5) - 11² = 125 - 121 = 4

Explanation

The letters in the given series follow a specific position-based pattern:

First letter: The first letter in each cluster is consistently Q.

Second letter: The numerical positions of the second letters are E (5), O (15), T (20), and Y (25). This sequence increases by +5 at each step. Thus, the missing second letter is 5 + 5 = 10, which corresponds to J.

Third letter: The third letter in each cluster is consistently S.

Fourth letter: The numerical positions of the fourth letters are C (3), M (13), R (18), and W (23). This sequence also increases by +5 at each step. Thus, the missing fourth letter is 3 + 5 = 8, which corresponds to H.

Combining these letters gives the cluster QJSH.

Explanation

The pattern in each row is that the third number is obtained by subtracting 1 from both the first and second numbers and then multiplying the results.

Mathematical relation: (First number - 1) × (Second number - 1) = Third number

Applying this relation to the first row: (9 - 1) × (7 - 1) = 8 × 6 = 48

Applying this relation to the second row: (12 - 1) × (5 - 1) = 11 × 4 = 44

Applying this relation to the third row: (8 - 1) × (13 - 1) = 7 × 12 = 84

Explanation

In each row, the third number is obtained by dividing the sum of the first two numbers by 3. The mathematical relation is:

(First number + Second number) ÷ 3 = Third number

For the first row: (86 + 82) ÷ 3 = 168 ÷ 3 = 56

For the second row: (74 + 67) ÷ 3 = 141 ÷ 3 = 47

Applying the same pattern to the third row: (54 + 48) ÷ 3 = 102 ÷ 3 = 34

Explanation

The relationship is established by dividing the seven-letter word into three parts: the first three letters, the middle (fourth) letter, and the last three letters. The first three letters and the last three letters are reversed, while the middle letter remains unchanged.

For the word INCLUDE, the first three letters INC are reversed to CNI, the middle letter L remains L, and the last three letters UDE are reversed to EDU, resulting in CNILEDU.

Similarly, for the word KEYNOTE, the first three letters KEY are reversed to YEK, the middle letter N remains N, and the last three letters OTE are reversed to ETO, resulting in YEKNETO.

Applying this same logic to the fifth term NOTABLY, the first three letters NOT are reversed to TON, the middle letter A remains A, and the last three letters BLY are reversed to YLB, which yields TONAYLB.

Explanation

The coding pattern involves two steps. First, each letter of the word is replaced by its opposite letter in the English alphabet, where the sum of their alphabetical positions is 27. Second, these opposite letters are divided into pairs of two and swapped.

For HEAT: The opposite letters of H, E, A, and T are S, V, Z, and G. Swapping the first pair (S, V) gives V, S, and swapping the second pair (Z, G) gives G, Z, resulting in VSGZ.

For CLAY: The opposite letters of C, L, A, and Y are X, O, Z, and B. Swapping the first pair (X, O) gives O, X, and swapping the second pair (Z, B) gives B, Z, resulting in OXBZ.

For BANK: The opposite letters of B, A, N, and K are Y, Z, M, and P. Swapping the first pair (Y, Z) gives Z, Y, and swapping the second pair (M, P) gives P, M, which yields ZYPM.

Explanation

To arrange the words in the order they would appear in an English dictionary, we compare them letter by letter from left to right.

All five words start with the letter I.

Comparing the second letters, Immense and Implied have the letter m, while Induce, Interim, and Invalid have the letter n. Since m comes before n in the alphabetical order, the words starting with Im will appear before those starting with In.

Comparing Immense and Implied, the third letter of Immense is m and the third letter of Implied is p. Since m comes before p, Immense (1) comes first, followed by Implied (3).

For the remaining words starting with In, we compare their third letters: d in Induce, t in Interim, and v in Invalid. Since d comes before t, and t comes before v, the alphabetical sequence is Induce (2), followed by Interim (4), and then Invalid (5).

Combining these steps gives the complete dictionary order as 1, 3, 2, 4, 5.

Explanation

The relationship followed by the other number-pairs is that the second number is the square of one-fourth of the first number, which is expressed by the formula y = (x ÷ 4)². For the pair 4:15, applying this relationship gives (4 ÷ 4)² = 1² = 1, which is not equal to 15. This makes it the odd pair that does not conform to the pattern.

Explanation

The coding scheme splits the word into two equal halves, swaps their positions, and then increments each letter by one position in the English alphabetical order.

For MEAL, the word is split into ME and AL. Swapping the halves gives ALME. Adding 1 to each letter (A → B, L → M, M → N, E → F) results in BMNF.

Similarly, for FOOD, the word is split into FO and OD. Swapping the halves gives ODFO. Adding 1 to each letter (O → P, D → E, F → G, O → P) results in PEGP.

Applying the same logic to FARE, the word is split into FA and RE. Swapping the halves gives REFA. Adding 1 to each letter yields: R + 1 = S E + 1 = F F + 1 = G A + 1 = B

This results in the code SFGB.

Explanation

To determine the number of people taller than R, we can arrange the seven friends in descending order of height from position 1 (tallest) to position 7 (shortest).

From the given clues: N is the tallest among all, so N occupies position 1. Only two people are taller than Q, which means Q occupies position 3. Only one person is shorter than M, which means M occupies position 6.

At this stage, the layout is: Position 1: N Position 2: Vacant Position 3: Q Position 4: Vacant Position 5: Vacant Position 6: M Position 7: Vacant

The remaining friends to be placed are L, O, P, and R.

We are given that R is taller than L, and L is taller than M (R > L > M). Since L is taller than M (position 6), both R and L must occupy positions taller than M, which means they must be placed in positions among 2, 4, and 5. O is not the shortest among all, so O cannot occupy position 7. Since R, L, and O cannot be in position 7, the remaining person P must be the shortest, occupying position 7.

Now, we place O, R, and L in positions 2, 4, and 5. Since R is taller than L, L occupies position 5, R occupies position 4, and O occupies position 2.

This gives the final arrangement from tallest to shortest: N > O > Q > R > L > M > P

Thus, the people taller than R are N, O, and Q. There are 3 people taller than R.

Explanation

The pattern followed by the other number pairs x:y is that the second number is the square of half of the first number increased by 1, which is formulated as y = ((x + 1)/2)². For the pair 45:576, applying this rule yields ((45 + 1)/2)² = 23² = 529. Because the second number is 576 instead of 529, this pair does not follow the common mathematical logic.

Explanation

To determine which conclusions follow, we analyze the logical relationships between the terms. Let R denote reds, Ro denote roses, V denote violets, and T denote tulips.

The statement that all reds are roses means the set R is entirely contained within the set Ro. The statement that no violet is a red means the sets V and R have no common elements. The statement that some tulips are violets means the sets T and V have a non-empty intersection.

For Conclusion I, some roses are violets, we know that V is disjoint from R, but V is not required to overlap with the rest of the set Ro. V can be entirely outside Ro, which means this conclusion does not logically follow.

For Conclusion II, no tulip is a red, we know that some tulips are violets, and no violet is red, which only guarantees that some tulips (those that are violets) are not red. This does not prevent other parts of the set T from overlapping with the set R. Thus, we cannot definitively conclude that no tulip is red, meaning this conclusion does not logically follow.

For Conclusion III, no rose is a tulip, there is no logical constraint that prevents the sets Ro and T from overlapping. It is entirely possible for some roses to be tulips. Thus, this conclusion also does not logically follow.

Explanation

The duration between 12th February 2011 and 12th February 2015 is exactly 4 years.

Among these years, 2012 is a leap year. Since its leap day (29th February 2012) falls within this period, we have 3 ordinary years and 1 leap year.

An ordinary year has 1 odd day, while a leap year has 2 odd days.

Total number of odd days between 12th February 2011 and 12th February 2015 = (3 × 1) + (1 × 2) = 5 odd days.

Adding 5 days to Saturday gives Thursday, meaning 12th February 2015 was a Thursday.

Consequently, 13th February 2015, being the very next day, was a Friday.

Explanation

Substituting the mathematical signs from option D (+, ×, ÷, =, -) into the expression:

25 + 7 × 56 ÷ 8 = 88 - 14

According to the BODMAS rule, the left-hand side is evaluated as follows:

First, division: 56 ÷ 8 = 7

Next, multiplication: 7 × 7 = 49

Finally, addition: 25 + 49 = 74

The right-hand side is evaluated as follows: 88 - 14 = 74

Since both sides are equal to 74, the equation is balanced.

Explanation

According to the decoding of the mathematical operators, the letters denote the following operations: A denotes + (addition) B denotes × (multiplication) C denotes − (subtraction) D denotes ÷ (division)

Replacing the letters in the given equation with their respective mathematical signs: 11 × (25 ÷ 5) + 7 × 3 − 24 + 1 × (16 ÷ 4)

Now, applying the BODMAS rule, solve the operations inside the brackets first: 25 ÷ 5 = 5 16 ÷ 4 = 4

Substituting these values back into the expression: 11 × 5 + 7 × 3 − 24 + 1 × 4

Next, perform the multiplication operations: 55 + 21 − 24 + 4

Finally, perform addition and subtraction operations: 76 − 24 + 4 = 56

Explanation

The consistent mathematical pattern followed by the number pairs is y = 2√x - 2, where x represents the first number and y represents the second number.

For the pair 4:18, substituting x = 4 into this relation gives: y = 2√4 - 2 = 2 × 2 - 2 = 2

Since the second number in the pair is 18 instead of 2, this pair fails to satisfy the common mathematical rule and is the odd one out.

Explanation

In each row of the pattern, the relationship between the numbers is: Third number = 8 × First number Second number = 4 × First number + 2

Applying this logic to the rows:

First row: Second number = 4 × 15 + 2 = 62 Third number = 8 × 15 = 120

Third row: Second number = 4 × 21 + 2 = 86 Third number = 8 × 21 = 168

Second row: Second number = 4 × 18 + 2 = 74 Third number = 8 × 18 = 144

Explanation

The relationship follows the pattern: (First digit * Second digit + Third digit) * (decreasing multiplier) + (increasing even addend). For 121: (1 * 2 + 1) * 3 + 0 = 9. For 212: (2 * 1 + 2) * 2 + 2 = 10. For 508: (5 * 0 + 8) * 1 + 4 = 12.

Explanation

To find the day of the week on 01 January 2012, we calculate the total number of days between 01 February 2011 and 01 January 2012.

The year 2011 is a non-leap year, so February has 28 days. The number of days in each month from February to December are: February: 28 days March: 31 days April: 30 days May: 31 days June: 30 days July: 31 days August: 31 days September: 30 days October: 31 days November: 30 days December: 31 days

Summing these days: 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30 + 31 = 334 days

To determine the number of odd days, we divide the total days by 7: 334 ÷ 7 = 47 weeks and 5 odd days

Adding 5 odd days to Tuesday (01 February 2011): Tuesday + 5 days = Sunday

Explanation

The given series follows an alternating pattern of addition and multiplication, where the operating numbers increase by 4 in each consecutive step.

First step: 150 + 4 = 154 Second step: 154 × 8 = 1232 Third step: 1232 + 12 = 1244 Fourth step: 1244 × 16 = 19904

Following this established sequence, the next operation is to add 20 to the previous term.

19904 + 20 = 19924

Explanation

Substituting the given operators into the equation where A is +, B is ×, C is -, and D is ÷, the expression becomes:

(84 ÷ 6) × 7 + (22 × 4) - 16 + (15 × 8)

Solving the operations inside the parentheses first: 84 ÷ 6 = 14 22 × 4 = 88 15 × 8 = 120

Now substitute these values back into the expression: 14 × 7 + 88 - 16 + 120

Perform the multiplication operation: 14 × 7 = 98

This simplifies the expression to: 98 + 88 - 16 + 120

Perform addition and subtraction: 186 - 16 + 120 = 170 + 120 = 290

Explanation

The series follows a specific mathematical pattern for each position of the letters: the first letter decreases by 7 (-7), the second letter decreases by 6 (-6), the third letter increases by 7 (+7), and the fourth letter increases by 6 (+6) in each step. Following this pattern for the last cluster MQMU (13, 17, 13, 21) gives F (13-7=6), K (17-6=11), T (13+7=20), and A (21+6=27/1), resulting in the cluster FKTA.

Explanation

The complete letter series is formed by the four-letter group GMDC repeating four times:

GMDC GMDC GMDC GMDC

Aligning this repeating pattern with the given series containing blanks:

_ M _ _ G _ D _ _ M _ C G _ D C

We find the missing letters for each blank from left to right:

The first blank is G The second blank is D The third blank is C The fourth blank is M The fifth blank is C The sixth blank is G The seventh blank is D The eighth blank is M

Combining these sequential letters gives GDCMCGDM.

Explanation

The pattern followed in each row is that the sum of the first two numbers divided by 4 yields the third number.

First row: (32 + 40) ÷ 4 = 72 ÷ 4 = 18

Second row: (38 + 46) ÷ 4 = 84 ÷ 4 = 21

Third row: (33 + 43) ÷ 4 = 76 ÷ 4 = 19

Explanation

Replacing the asterisks in the expression 50 5 10 1 5 * 5 with the symbols from option A, which are ÷, =, ×, +, and –, gives the equation:

50 ÷ 5 = 10 × 1 + 5 – 5

Evaluating the left-hand side of the equation: 50 ÷ 5 = 10

Evaluating the right-hand side of the equation following the order of operations: First, perform the multiplication: 10 × 1 = 10

Next, perform the addition and subtraction: 10 + 5 – 5 = 10

Both sides of the equation yield 10, which successfully balances the equation.

Explanation

The relationship between the terms in each pair follows the mathematical pattern where the second term is obtained by multiplying the first term by 4 and then subtracting 5.

For the first pair: 35 × 4 - 5 = 140 - 5 = 135

For the third pair: 24 × 4 - 5 = 96 - 5 = 91

Applying the same formula to the second pair with the first term 17: 17 × 4 - 5 = 68 - 5 = 63

Explanation

The relationship between the terms follows the pattern where the second term is obtained by multiplying the first term by 6 and then subtracting 9.

For the first pair: 13 × 6 - 9 = 78 - 9 = 69

For the third pair: 23 × 6 - 9 = 138 - 9 = 129

Applying the same pattern to the second pair: 17 × 6 - 9 = 102 - 9 = 93

Explanation

The coding pattern involves taking the alphabetical positional value of each letter in the word and adding 1 to it.

For the word GOLD: G is the 7th letter of the English alphabet, so 7 + 1 = 8. O is the 15th letter of the English alphabet, so 15 + 1 = 16. L is the 12th letter of the English alphabet, so 12 + 1 = 13. D is the 4th letter of the English alphabet, so 4 + 1 = 5.

Combining these resulting numbers sequentially gives 816135.

Explanation

The coding pattern follows an alternating sequence of adding and subtracting 2 from the alphabetical position of each letter in the word.

For the word SAVIOUR: S + 2 = U A - 2 = Y V + 2 = X I - 2 = G O + 2 = Q U - 2 = S R + 2 = T

Applying the same pattern of +2, -2, +2, -2, +2, -2, +2 to the word HEIGHTS: H + 2 = J E - 2 = C I + 2 = K G - 2 = E H + 2 = J T - 2 = R S + 2 = U

This yields the coded word JCKEJRU.

Explanation

To arrange the words in alphabetical order as they appear in an English dictionary, we compare them letter by letter. All five words begin with the prefix Cha.

Comparing the fourth letters of the words, we find p in Chapel and Chapter, and r in Charger, Charcoal, and Character. Since p comes before r in the alphabet, Chapel and Chapter will appear before the other three words.

Comparing Chapel and Chapter, the fifth letters are e and t. Since e comes before t, Chapel (2) is first, followed by Chapter (3). This gives the starting sequence 2, 3.

For the remaining words, Charger, Charcoal, and Character, we compare their fifth letters, which are g, c, and a, respectively. Arranging these alphabetically, a comes before c, which comes before g. Therefore, Character (5) comes first, followed by Charcoal (4), and then Charger (1). This gives the sequence 5, 4, 1.

Combining both sequences yields the correct dictionary order: 2, 3, 5, 4, 1.

Explanation

The relation between the pairs of numbers follows the pattern where the first number is multiplied by six less than itself to obtain the second number:

First number × (First number - 6) = Second number

Applying this to the first pair: 18 × (18 - 6) = 18 × 12 = 216

Applying this to the second pair: 20 × (20 - 6) = 20 × 14 = 280

Applying this same logic to the fifth number: 12 × (12 - 6) = 12 × 6 = 72

Explanation

To determine the age order of the seven friends, we can arrange them from oldest (rank 1) to youngest (rank 7).

Since B is the oldest among all, B occupies rank 1.

We are told that only two people are younger than C. This places C at rank 5, meaning ranks 6 and 7 are younger than C.

Since C is older than D, and D is not the youngest (rank 7), D must occupy rank 6. The remaining rank 7 is occupied by A.

We are given that G is older than C, and E is older than G but younger than F, which gives the relation F > E > G > C. Since C is at rank 5, the three friends F, E, and G must occupy ranks 2, 3, and 4 in that exact order. Thus, F is at rank 2, E is at rank 3, and G is at rank 4.

The final sequence from oldest to youngest is B > F > E > G > C > D > A.

The persons younger than E are G, C, D, and A, which makes a total of 4 persons.

Explanation

The pattern is based on rearranging the positions of the letters in each six-letter word.

Assigning position numbers 1 to 6 from left to right for each word: 1 2 3 4 5 6

In the first pair, GRAPES (1 2 3 4 5 6) is rearranged to SAREPG, which corresponds to the position sequence: 6 3 2 5 4 1

In the second pair, VERBAL (1 2 3 4 5 6) is rearranged to LREABV following the exact same position sequence: 6 3 2 5 4 1

Applying this same position sequence (6 3 2 5 4 1) to NUMBER (1 2 3 4 5 6): The 6th letter is R The 3rd letter is M The 2nd letter is U The 5th letter is E The 4th letter is B The 1st letter is N

Combining these letters in the sequence 6 3 2 5 4 1 gives RMUEBN.

Explanation

Replacing the asterisks with the signs +, -, =, and + in order yields:

27 + 3 - 10 = 10 + 10

Calculating the Left-Hand Side (LHS): 27 + 3 - 10 = 30 - 10 = 20

Calculating the Right-Hand Side (RHS): 10 + 10 = 20

Since LHS = RHS = 20, the mathematical relation is balanced and correct.

Explanation

Replacing the asterisks with the mathematical signs +, -, =, and × yields the equation:

46 + 75 - 41 = 16 × 5

Solving the left-hand side: 46 + 75 - 41 = 121 - 41 = 80

Solving the right-hand side: 16 × 5 = 80

Both sides of the equation simplify to 80, which balances the expression.

Explanation

If 2nd January 2008 was a Wednesday, then 1st January 2008 was a Tuesday.

To find the day of the week on 1st January 2012, we calculate the total number of odd days between 1st January 2008 and 1st January 2012:

2008 is a leap year, which has 2 odd days. 2009 is an ordinary year, which has 1 odd day. 2010 is an ordinary year, which has 1 odd day. 2011 is an ordinary year, which has 1 odd day.

Total odd days = 2 + 1 + 1 + 1 = 5 odd days.

Adding 5 days to Tuesday (1st January 2008) results in Sunday.

Explanation

The pattern followed by the other pairs is that the second number is the product of the first number and a number that is two less than it, represented by the relation x × (x - 2). For the first number 17, this rule yields 17 × (17 - 2) = 17 × 15 = 255. Since the second number given in this pair is 238, it does not follow this pattern.

Explanation

The series follows a specific addition pattern for each corresponding letter in the clusters based on their alphabetical positions.

For the first letter, there is a constant increase of +1: U (21) + 1 = V (22) V (22) + 1 = W (23) W (23) + 1 = X (24) X (24) + 1 = Y (25)

For the second letter, there is a constant increase of +3: B (2) + 3 = E (5) E (5) + 3 = H (8) H (8) + 3 = K (11) K (11) + 3 = N (14)

For the third letter, there is a constant increase of +5: E (5) + 5 = J (10) J (10) + 5 = O (15) O (15) + 5 = T (20) T (20) + 5 = Y (25)

For the fourth letter, there is a constant increase of +7: J (10) + 7 = Q (17) Q (17) + 7 = X (24) X (24) + 7 = E (31, which is 5 in alphabetical cycle) E (5) + 7 = L (12)

Applying these additions to the second cluster VEJQ yields W, H, O, and X respectively.

Explanation

The series is solved by analyzing the alphabetical positions of each letter in the clusters.

For the first letter, the positions decrease by 2 in each step: Z (26) minus 2 gives X (24), which then minus 2 gives V (22), and so on.

For the second letter, the positions decrease by 2 in each step: O (15) minus 2 gives M (13), which then minus 2 gives K (11), and so on.

For the third letter, the positions increase by 2 in each step: F (6) plus 2 gives H (8), which then plus 2 gives J (10), and so on.

For the fourth letter, the positions increase by 2 in each step: B (2) plus 2 gives D (4), which then plus 2 gives F (6), and so on.

Putting the letters together yields the cluster XMHD.

Explanation

The given sequence is an alternating series composed of two distinct arithmetic progressions.

The first progression consists of the odd-positioned terms: 348, 339, and 330. Each subsequent term in this sub-series decreases by 9, as shown by 348 - 9 = 339, and 339 - 9 = 330.

The second progression consists of the even-positioned terms: 353, ?, and 371. Each subsequent term in this sub-series increases by 9. Applying this pattern, we add 9 to the first term of this progression to find the missing term: 353 + 9 = 362. We can verify this with the next term in the progression: 362 + 9 = 371.

Explanation

The given series follows an alternating pattern of adding 5 and dividing by 2 to find the next term.

17 + 5 = 22 22 ÷ 2 = 11 11 + 5 = 16 16 ÷ 2 = 8 8 + 5 = 13

Applying the next operation in the sequence, which is division by 2, to the last term: 13 ÷ 2 = 6.5

Explanation

According to the given statements, some plastics are metals and all metals are stones. Since the entire set of metals is contained within the set of stones, any plastic that is a metal is also a stone. This makes conclusion I, some stones are plastics, logically true.

Additionally, some woods are metals and all metals are stones. Since the entire set of metals is inside the set of stones, the woods that are metals must also be stones. This makes conclusion II, some woods are stones, logically true.

Regarding conclusion III, while all metals are stones, the reverse is not necessarily true, so we cannot conclude that all stones are metals.