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

Explanation

To find the day of the week on 21st June 2011, we calculate the number of odd days between 21st June 2007 and 21st June 2011.

The difference in years is 2011 − 2007 = 4 years.

In this 4-year interval, there is 1 leap year (2008) and 3 ordinary years (2009, 2010, and 2011). Since the transition from June 2007 to June 2008 crosses 29th February 2008, that period contributes 2 odd days.

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

Total odd days = (3 × 1) + (1 × 2) = 5 odd days.

We add these 5 odd days to the reference day, Thursday: Thursday + 5 days = Tuesday.

Explanation

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

Comparing the first letter, all words begin with A.

Comparing the second letter, Abduction (4) has b, while the other words have d. Since b comes before d alphabetically, Abduction (4) is the first word.

Comparing the third letter of the remaining words, Addiction (3) has d, Adequate (1) has e, Adoption (2) has o, and Advertisement (5) has v.

Arranging these third letters in alphabetical order gives d, then e, then o, and finally v. This places Addiction (3) second, Adequate (1) third, Adoption (2) fourth, and Advertisement (5) fifth, yielding the sequence 4, 3, 1, 2, 5.

Explanation

The relationship represented in each pair is that of an object and the specific hand tool used to drive or operate it. Wrenches are used to tighten or loosen nuts and bolts, and a screwdriver is used to drive screws. In the same way, a hammer is the tool used to drive or extract nails.

Explanation

The given series follows an alternating pattern of multiplication and addition using consecutive natural numbers:

First term × 2 = 10 × 2 = 20 Second term + 3 = 20 + 3 = 23 Third term × 4 = 23 × 4 = 92 Fourth term + 5 = 92 + 5 = 97 Fifth term × 6 = 97 × 6 = 582

Following this pattern, the missing number is 92.

Explanation

The coding pattern is based on writing the standard alphabetical positions of the letters (A = 1, B = 2, ..., Z = 26) of each word in reverse order, starting from the last letter to the first letter.

For the word WELL, the alphabetical positions of the letters are W = 23, E = 5, L = 12, and L = 12. Writing these values in reverse order (corresponding to L, L, E, W) gives 12, 12, 5, and 23. Concatenating these numbers results in 1212523.

Explanation

In the pair 22:66, the second number is obtained by multiplying the first number by 3, as 22 × 3 = 66. This is the only pair that does not follow the pattern where the second number is four times the first number.

Explanation

The given number series follows a pattern where each subsequent term is obtained by multiplying the preceding term by consecutive integers starting from 1, and then adding consecutive integers starting from 2.

The step-by-step calculations are:

11 × 1 + 2 = 13

13 × 2 + 3 = 29

29 × 3 + 4 = 91

91 × 4 + 5 = 369

Following the same logic, the missing term is:

369 × 5 + 6 = 1845 + 6 = 1851

Explanation

A bonnet is the front part of a car. Similarly, a bow is the front part of a boat. Thus, the relationship is based on identifying the front-most part of the respective vehicles.

Explanation

The coding pattern involves dividing each six-letter word into three consecutive pairs of letters and reversing the order of the letters within each pair.

For CLIENT: The first pair CL is reversed to LC. The second pair IE is reversed to EI. The third pair NT is reversed to TN. Combining them gives LCEITN.

For CLOSED: The first pair CL is reversed to LC. The second pair OS is reversed to SO. The third pair ED is reversed to DE. Combining them gives LCSODE.

Applying this same rule to FAMILY: The first pair FA is reversed to AF. The second pair MI is reversed to IM. The third pair LY is reversed to YL. Combining these three reversed pairs yields AFIMYL.

Explanation

The series follows a specific logical pattern for each letter position in the clusters.

For the first letter of each cluster, the alphabetical positions decrease by 3: W (23) - 3 = T (20) T (20) - 3 = Q (17) Q (17) - 3 = N (14) N (14) - 3 = K (11)

For the second letter of each cluster, the alphabetical positions increase by 3: D (4) + 3 = G (7) G (7) + 3 = J (10) J (10) + 3 = M (13) M (13) + 3 = P (16)

For the third letter of each cluster, the alphabetical positions decrease by 3: V (22) - 3 = S (19) S (19) - 3 = P (16) P (16) - 3 = M (13) M (13) - 3 = J (10)

Combining these results gives the letter-cluster KPJ.

Explanation

The pattern followed in the given number pairs is: Second term = (First term × 2) - 7

Applying this relation to the first pair: 14 × 2 - 7 = 28 - 7 = 21

Applying the same relation to the third pair: 47 × 2 - 7 = 94 - 7 = 87

Applying the same relation to find the missing term: 34 × 2 - 7 = 68 - 7 = 61

Explanation

The pattern in each row is that the third number is obtained by adding the first and the second numbers.

In the first row, the calculation is 86 + 72 = 158.

In the second row, the calculation is 98 + 111 = 209.

Following the same logic for the third row, the calculation is 76 + 65 = 141.

Explanation

Substituting the mathematical signs from option D in order into the equation:

62 + 17 × 6 - 81 = 23 × 2 + 37

Following the BODMAS rule, solve the multiplication on both sides:

Left-hand side (LHS): 62 + 102 - 81 164 - 81 83

Right-hand side (RHS): 46 + 37 83

Since LHS = RHS = 83, the equation is balanced.

Explanation

To arrange the given words in alphabetical order as they would appear in an English dictionary, we compare their letters from left to right.

All five words start with the letters Sa. Comparing the third letter, l comes before n, which groups Salesman, Salmon, and Salvation ahead of Sanitization and Sanctuary.

Within the first group, we compare the fourth letters: e in Salesman, m in Salmon, and v in Salvation. Since e comes before m, and m comes before v, the correct sequence is Salesman (5), Salmon (4), and Salvation (3).

Within the second group, we compare the fourth letters: i in Sanitization and c in Sanctuary. Since c comes before i, Sanctuary (2) comes before Sanitization (1).

Combining both groups yields the final dictionary order: 5, 4, 3, 2, 1.

Explanation

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

All five words begin with the letters Cu.

Comparing the third letter of each word: In Cucumber, the third letter is c. In Culinary and Culminate, the third letter is l. In Curator and Curriculum, the third letter is r.

Since c comes before l, and l comes before r in the alphabet, Cucumber (5) is the first word in the sequence.

Next, we compare Culinary (4) and Culminate (2) which both share Cul as their first three letters. Comparing their fourth letters, i in Culinary comes before m in Culminate, so Culinary (4) comes before Culminate (2).

Finally, we compare Curator (1) and Curriculum (3) which both share Cur as their first three letters. Comparing their fourth letters, a in Curator comes before r in Curriculum, so Curator (1) comes before Curriculum (3).

Putting them all together, the correct alphabetical sequence is 5, 4, 2, 1, 3.

Explanation

Applying the operators sequentially from Option C to replace the asterisks in the expression 25 5 10 2 4 * 10 gives:

25 + 5 - 10 ÷ 2 × 4 = 10

According to the BODMAS rule, the operations are performed in the order of Division, Multiplication, Addition, and Subtraction.

First, perform the division: 10 ÷ 2 = 5

Substituting this back into the equation: 25 + 5 - 5 × 4 = 10

Next, perform the multiplication: 5 × 4 = 20

Substituting this back into the equation: 25 + 5 - 20 = 10

Now, perform the addition: 25 + 5 = 30

Substituting this back into the equation: 30 - 20 = 10

Finally, perform the subtraction: 10 = 10

Since the left-hand side equals the right-hand side, the equation is balanced.

Explanation

The pattern followed by the numbers in each row is that the cube of the first number added to the square of the third number yields the second number.

For the first row, 2³ + 7² = 8 + 49 = 57.

For the second row, 6³ + 3² = 216 + 9 = 225.

Applying the same logic to the third row, we get 5³ + 2² = 125 + 4 = 129.

Explanation

From the statement that all compasses are sharpeners and all sharpeners are erasers, we can transitively conclude that all compasses are erasers. This makes conclusion I logically follow.

Since all compasses are erasers, it directly implies that some part of the eraser group consists of compasses. Thus, some erasers are compasses, which makes conclusion III logically follow.

There is no relationship established between pencils and compasses or sharpeners, meaning conclusion II does not necessarily follow.

Explanation

The series is divided into four groups of five letters each. By placing the letters K, Y, P, and W sequentially in the blanks, the series becomes: ABZKP ABYKP ABXKP ABWKP

In each group of five letters, the first two letters are always AB and the last two letters are always KP. The middle letter in each group decreases by one in reverse alphabetical order from Z to W: Z in the first group, Y in the second group, X in the third group, and W in the fourth group.

This perfectly completes the pattern with the sequence K, Y, P, W.

Explanation

The given series follows a pattern where the difference between consecutive terms decreases by cubes of consecutive natural numbers starting from 2.

1724 - 2³ = 1724 - 8 = 1716 1716 - 3³ = 1716 - 27 = 1689 1689 - 4³ = 1689 - 64 = 1625 1625 - 5³ = 1625 - 125 = 1500

Following the same logic, the next term is obtained by subtracting 6³ from 1500:

1500 - 6³ = 1500 - 216 = 1284

Explanation

In the pair 24:8, the division of the first number by the second number is 24 ÷ 8 = 3. In all other pairs, this division consistently yields a quotient of 6, such as 42 ÷ 7 = 6, 36 ÷ 6 = 6, and 48 ÷ 8 = 6. This makes 24:8 the odd pair as it does not follow the rule of multiplying the second number by 6 to obtain the first.

Explanation

Applying the operators given in option C to the expression: 41 × 2 + 36 ÷ 6 − 57 = 7 × 4 + 3

Solving the Left Hand Side (LHS) using the BODMAS rule: First, perform the division: 36 ÷ 6 = 6 This simplifies the LHS to: 41 × 2 + 6 − 57

Next, perform the multiplication: 41 × 2 = 82 The LHS becomes: 82 + 6 − 57

Finally, perform addition and subtraction: 88 − 57 = 31

Now, solving the Right Hand Side (RHS) using the BODMAS rule: First, perform the multiplication: 7 × 4 = 28 The RHS becomes: 28 + 3 = 31

Since LHS = RHS = 31, the equation is balanced.

Explanation

By substituting the signs from option C, which correspond to division, addition, equality, and division (÷, +, =, ÷), into the equation:

78 ÷ 3 + 14 = 80 ÷ 2

Evaluating the Left Hand Side (LHS) using BODMAS rules: 78 ÷ 3 + 14 = 26 + 14 = 40

Evaluating the Right Hand Side (RHS): 80 ÷ 2 = 40

Since LHS = RHS = 40, the equation is balanced.

Explanation

To find the relationship, break down the statement made by Vijay into two simpler parts.

First, the phrase "Her sister's mother" refers to the lady's mother.

Second, the phrase "my father's daughter" refers to Vijay's sister. Therefore, "the sister of my father's daughter" is also Vijay's sister.

Equating the two parts, the lady's mother is Vijay's sister. Since the lady is the daughter of Vijay's sister, she is related to Vijay as his sister's daughter.

Explanation

The given series is an alternating series consisting of two separate sub-series.

The first sub-series contains the numbers at the odd positions: 28, 25, and 22. In this sub-series, each subsequent term is obtained by subtracting 3 from the preceding term: 28 - 3 = 25 25 - 3 = 22

The second sub-series contains the numbers at the even positions: 40, ?, and 46. In this sub-series, each subsequent term is obtained by adding 3 to the preceding term: 40 + 3 = 43 43 + 3 = 46

Explanation

The sequence of operators that balances the equation is division (÷), subtraction (-), addition (+), and multiplication (×).

Using these operators to replace the signs: 25 ÷ 5 - 10 + 2 × 8 = 11

Using the BODMAS rule to evaluate the left-hand side:

Perform division first: 25 ÷ 5 = 5

The equation becomes: 5 - 10 + 2 × 8 = 11

Next, perform multiplication: 2 × 8 = 16

The equation becomes: 5 - 10 + 16 = 11

Perform addition: 5 + 16 = 21

Finally, perform subtraction: 21 - 10 = 11

This yields 11 = 11, which balances the equation.

The division sign (÷) corresponds to the first symbol in option D.

Explanation

The series is formed by applying a specific alphabetical shift to each position of the letter clusters.

For the first letter, there is a constant subtraction of 4 positions. Subtracting 4 from E (5) gives A (1), which becomes W (23) after subtracting 4, then S (19) after subtracting 4, and finally O (15).

For the second letter, there is a constant addition of 6 positions. Adding 6 to T (20) gives Z (26), which becomes F (6) after adding 6, then L (12) after adding 6, and finally R (18).

For the third letter, there is a constant subtraction of 8 positions. Subtracting 8 from R (18) gives J (10), which becomes B (2) after subtracting 8, then T (20) after subtracting 8, and finally L (12).

For the fourth letter, there is a constant addition of 2 positions. Adding 2 to E (5) gives G (7), which becomes I (9) after adding 2, then K (11) after adding 2, and finally M (13).

Combining these results gives the letter cluster ORLM.

Explanation

The coding pattern uses the opposite pairs of the English alphabet, where the sum of the numerical positions of the original letter and its coded letter is 27.

Applying this rule to each letter of the word ARCHIVE:

A is the 1st letter from the start, and its opposite is Z, the 1st letter from the end (1 + 26 = 27). R is the 18th letter from the start, and its opposite is I, the 18th letter from the end (18 + 9 = 27). C is the 3rd letter from the start, and its opposite is X, the 3rd letter from the end (3 + 24 = 27). H is the 8th letter from the start, and its opposite is S, the 8th letter from the end (8 + 19 = 27). I is the 9th letter from the start, and its opposite is R, the 9th letter from the end (9 + 18 = 27). V is the 22nd letter from the start, and its opposite is E, the 22nd letter from the end (22 + 5 = 27). E is the 5th letter from the start, and its opposite is V, the 5th letter from the end (5 + 22 = 27).

Combining these opposite letters in sequence gives ZIXSREV.

Explanation

By converting the letters to their corresponding numerical positions in the English alphabet (A = 1, B = 2, ..., Z = 26), we can determine the pattern for each letter in the clusters.

First letter of each cluster decreases by 5: W (23) - 5 = R (18) R (18) - 5 = M (13) M (13) - 5 = H (8) H (8) - 5 = C (3)

Second letter of each cluster decreases by 5: U (21) - 5 = P (16) P (16) - 5 = K (11) K (11) - 5 = F (6) F (6) - 5 = A (1)

Third letter of each cluster decreases by 5: T (20) - 5 = O (15) O (15) - 5 = J (10) J (10) - 5 = E (5) E (5) - 5 = Z (26)

The resulting letters are C, A, and Z, which form the cluster CAZ.

Explanation

The given number series is 56, 68, ?, 128, 176, 236.

Analyzing the differences between consecutive terms reveals a pattern of consecutive multiples of 12:

68 - 56 = 12 176 - 128 = 48 236 - 176 = 60

The differences between consecutive terms increase by 12 each time, forming the sequence: 12, 24, 36, 48, 60.

Applying this pattern to find the missing term:

68 + 24 = 92

To verify, adding the next multiple of 12 (36) to this result should yield the subsequent term in the series:

92 + 36 = 128

The pattern is consistent and confirms the missing number.

Explanation

The relationship among the numbers in each set (A, B, C) follows the logic: (A ÷ B) + B = C

Applying this logic to the given sets: For (75, 25, 28): (75 ÷ 25) + 25 = 3 + 25 = 28

For (136, 34, 38): (136 ÷ 34) + 34 = 4 + 34 = 38

Following the same logic for the set (105, 35, 38): (105 ÷ 35) + 35 = 3 + 35 = 38

Explanation

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

For the word CAPON: C + 2 = E A - 2 = Y P + 2 = R O - 2 = M N + 2 = P

For the word DECOY: D + 2 = F E - 2 = C C + 2 = E O - 2 = M Y + 2 = A

Applying this same pattern to the word POWER: P + 2 = R O - 2 = M W + 2 = Y E - 2 = C R + 2 = T

This gives the coded word RMYCT.

Explanation

Substituting the signs in option D into the given equation, we get:

96 × 6 ÷ 24 = 49 - 25

Solving the Left Hand Side (LHS): 96 × 6 ÷ 24 = 96 × (6 ÷ 24) = 96 × (1/4) = 24

Solving the Right Hand Side (RHS): 49 - 25 = 24

Since LHS = RHS = 24, this combination balances the equation.

Explanation

By replacing the second plus sign (+) in Option A with the division sign (÷) due to a typographical representation, we get the sequential signs as +, ÷, -, ×, =.

Substituting these signs into the equation: 57 + 35 ÷ 7 - 14 × 2 = 34

Applying the BODMAS rule: First, perform the division: 35 ÷ 7 = 5 The equation becomes: 57 + 5 - 14 × 2 = 34

Next, perform the multiplication: 14 × 2 = 28 The equation becomes: 57 + 5 - 28 = 34

Next, perform the addition: 57 + 5 = 62 The equation becomes: 62 - 28 = 34

Finally, perform the subtraction: 62 - 28 = 34 34 = 34

The LHS equals the RHS, which balances the equation.

Explanation

The numbers in each row follow a consistent mathematical pattern:

Second number = First number × 7 - 3 Third number = Second number × 3 + 7 (which simplifies to: First number × 21 - 2)

Applying this pattern to each row:

First row: 6 × 7 - 3 = 42 - 3 = 39 39 × 3 + 7 = 117 + 7 = 124

Third row: 11 × 7 - 3 = 77 - 3 = 74 74 × 3 + 7 = 222 + 7 = 229

Second row: 8 × 7 - 3 = 56 - 3 = 53 53 × 3 + 7 = 159 + 7 = 166

Explanation

The pattern followed in each row is that the third number is obtained by multiplying the first number, the second number, and a constant value of 5.

For the first row: 3 × 2 × 5 = 30

For the second row: 7 × 5 × 5 = 175

Following the same logic for the third row: 4 × 6 × 5 = 120

Explanation

The pattern of rearrangement of a six-letter word is as follows:

The letters at positions 1 and 2 swap their places with the letters at positions 4 and 5, while the letters at positions 3 and 6 remain in their original positions.

Applying this pattern to the word DENIAL: The letters at positions 1 and 2 (D, E) swap with those at positions 4 and 5 (I, A). The letters at positions 3 (N) and 6 (L) remain unchanged. This results in the word IANDEL.

Applying the same pattern to the word OBJECT: The letters at positions 1 and 2 (O, B) swap with those at positions 4 and 5 (E, C). The letters at positions 3 (J) and 6 (T) remain unchanged. This results in the word ECJOBT.

Applying this pattern to the word FLAVOR: The letters at positions 1 and 2 (F, L) swap with those at positions 4 and 5 (V, O). The letters at positions 3 (A) and 6 (R) remain unchanged. This results in the word VOAFLR.

Explanation

The pattern in each pair of terms is that the letters of the first term are reversed to form the second term.

For the first pair, reversing the letters of YAR gives RAY. For the second pair, reversing the letters of TCA gives ACT.

Following the same logic for the third pair, reversing the letters of TAB gives BAT.

Explanation

To balance the given equation, substitute the mathematical signs from option D, where the first operator is division ÷:

64 ÷ 4 + 3 = 71 - 19 × 5 + 43

Solving the Left Hand Side (LHS) using the BODMAS rule: 64 ÷ 4 + 3 Performing division first: 64 ÷ 4 = 16 Performing addition: 16 + 3 = 19

Solving the Right Hand Side (RHS) using the BODMAS rule: 71 - 19 × 5 + 43 Performing multiplication first: 19 × 5 = 95 Substituting this back gives: 71 - 95 + 43 Performing addition and subtraction from left to right: 71 + 43 - 95 114 - 95 = 19

Since LHS = RHS = 19, the equation is balanced.

Explanation

Let us break down the relation mentioned by Taran:

First, the husband of Taran is referred to as "my husband".

Second, the father-in-law of Taran's husband is Taran's father.

Third, the mother of Taran's father is Taran's grandmother.

Since the woman in the picture is Taran's grandmother, Taran is the granddaughter of that woman.

Explanation

The general pattern followed by the number pairs x:y is x = n² - 1 and y = n³ - 1, where n is a positive integer. For n = 2, we get 2² - 1 = 3 and 2³ - 1 = 7. For n = 4, we get 4² - 1 = 15 and 4³ - 1 = 63. For n = 3, we get 3² - 1 = 8 and 3³ - 1 = 26. The pair 23:123 does not follow this rule, as for n = 5 the expected pair is 24:124 because 5² - 1 = 24 and 5³ - 1 = 124.

Explanation

The pattern of the series is based on double differences. First, find the differences between consecutive terms: 9 - 4 = 5 17 - 9 = 8 30 - 17 = 13 50 - 30 = 20 81 - 50 = 31 125 - 81 = 44

Next, find the differences between these consecutive difference values: 8 - 5 = 3 13 - 8 = 5 20 - 13 = 7 31 - 20 = 11 44 - 31 = 13

The resulting second-level differences (3, 5, 7, 11, 13) represent the sequence of consecutive prime numbers.

Following this pattern, the next prime number is 17.

Adding this prime number to the last first-level difference gives: 44 + 17 = 61

Adding this value to the last term of the series gives the next number: 125 + 61 = 186

Explanation

Cow and Bull are terms representing the same category of animal (cattle). Similarly, Mice and Mouse represent the same category of animal (rodents), with Mouse being the singular form of Mice.

Explanation

Replacing the alphabet letters with their respective mathematical operators as given in the question: A represents + B represents × C represents - D represents ÷

The given equation is: 41 C 29 A (38 B 3) D 19 A 61 C 17

Substituting the operators: 41 - 29 + (38 × 3) ÷ 19 + 61 - 17

Following the BODMAS rule, first solve the bracket: 38 × 3 = 114

Substitute this value back into the expression: 41 - 29 + 114 ÷ 19 + 61 - 17

Next, perform division: 114 ÷ 19 = 6

Substitute this value: 41 - 29 + 6 + 61 - 17

Now perform the addition and subtraction from left to right: 12 + 6 + 61 - 17 = 18 + 61 - 17 = 79 - 17 = 62

Explanation

The relation between the terms in each pair is based on the square root of the first number. For any pair A : B, the relationship is defined by the formula B = √A - 1.

Applying this to the first pair: √25 - 1 = 5 - 1 = 4

Applying this to the third pair: √225 - 1 = 15 - 1 = 14

Applying the same logic to the middle pair: √64 - 1 = 8 - 1 = 7

Explanation

The given sequence is an arithmetic progression where each subsequent term is obtained by subtracting a constant value of 43 from the preceding term.

569 - 43 = 526 526 - 43 = 483 483 - 43 = 440 440 - 43 = 397

Following this pattern, the next term in the series is:

397 - 43 = 354

Explanation

The coding scheme is based on alternating letters from the end and the beginning of the word. Specifically, for a word of length N, the letters are rearranged by taking the N-th letter, then the 1st letter, then the (N-1)-th letter, then the 2nd letter, and so on.

In the case of FLEECE, which has 6 letters, this pattern of positions (6, 1, 5, 2, 4, 3) yields EFCLEE.

For OVERCOAT, which has 8 letters, the pattern of positions (8, 1, 7, 2, 6, 3, 5, 4) yields TOAVOECR.

Applying this pattern to MITTEN, which has 6 letters: The 6th letter is N The 1st letter is M The 5th letter is E The 2nd letter is I The 4th letter is T The 3rd letter is T

Combining these in sequence gives NMEITT.

Explanation

Replacing the asterisks with the signs in option B gives the equation 31 + 29 - 43 = 85 ÷ 5. Evaluating both sides, we get 60 - 43 = 17 on the left and 85 ÷ 5 = 17 on the right, which balances the equation.

Explanation

The series follows a specific pattern for each of the four positions in the letter-clusters.

For the first letter, the alphabetical positions decrease by 10 in each step: Z (26) minus 10 is P (16), P (16) minus 10 is F (6), F (6) minus 10 is V (22), and V (22) minus 10 is L (12).

For the second letter, the alphabetical positions decrease by 7 in each step: F (6) minus 7 is Y (25), Y (25) minus 7 is R (18), R (18) minus 7 is K (11), and K (11) minus 7 is D (4).

For the third letter, the sequence cycles through the vowels (A, E, I, O, U) sequentially: O goes to U, U cycles back to A, A goes to E, and E goes to I.

For the fourth letter, the alphabetical positions decrease by 4 in each step: E (5) minus 4 is A (1), A (1) minus 4 is W (23), W (23) minus 4 is S (19), and S (19) minus 4 is O (15).

Putting these letters together gives LDIO.

Explanation

The common mathematical operation followed in the pairs is that the second number is two-thirds of the first number, representing a ratio of 3:2. Multiplying the first number 33 by 2/3 yields 22. Because the second number in this pair is 24 instead of 22, it does not conform to the pattern followed by the rest of the pairs.