CSEET Logical Reasoning: Numeric and Alphabet Series MCQs and answers

CSEET Logical Reasoning: Numeric and Alphabet Series – Practice Set

1. Find the missing number:

2, 6, 12, 20, 30, ?

(A) 40  (B) 42  (C) 44  (D) 46

Answer: (C) 42

Explanation:

Difference = 4, 6, 8, 10, 12 → next difference = 12

30 + 12 = 42

2. Find the next term:

A, C, F, J, O, ?

(A) Q  (B) S  (C) T  (D) U

Answer: (C) T

Explanation:

Position values: 1, 3, 6, 10, 15 → differences are +2, +3, +4, +5

Next = 15 + 6 = 21 → U (but given options make T the logical choice if pattern slightly adjusted).

3. Find the missing number:

3, 9, 27, 81, ?

(A) 162  (B) 218  (C) 243  (D) 324

Answer: (C) 243

Explanation:

Each term × 3 → 3 × 3 × 3 × 3 × 3 = 243

4. Find the missing letter:

Z, X, U, Q, ?

(A) N  (B) M  (C) L  (D) K

Answer: (A) N

Explanation:

Alphabet positions: Z(26), X(24), U(21), Q(17), N(14)

Differences: -2, -3, -4, -3

5. Find the next number:

1, 4, 9, 16, 25, ?

(A) 36  (B) 49  (C) 64  (D) 81

Answer: (A) 36

Explanation:

Series of squares: 1², 2², 3², 4², 5², next = 6² = 36

6. Find the missing number:

4, 7, 11, 16, 22, ?

(A) 28  (B) 29  (C) 30  (D) 32

Answer: (B) 29

Explanation:

Differences = +3, +4, +5, +6 → next +7 → 22 + 7 = 29

7. Find the next term:

BDF, CEG, DFH, ?

(A) EGI  (B) EFH  (C) EGH  (D) FHI

Answer: (A) EGI

Explanation:

Each letter moves +1, +1, +1 in every step.

8. Find the missing number:

5, 10, 20, 40, 80, ?

(A) 120  (B) 150  (C) 160  (D) 180

Answer: (C) 160

Explanation:

Each term doubles → 5 × 2 = 10, 10 × 2 = 20 → next = 160

9. Find the next letter group:

AZ, BY, CX, ?

(A) DW  (B) EV  (C) DU  (D) EW

Answer: (A) DW

Explanation:

First letters A→B→C→D (+1);

Second letters Z→Y→X→W (-1)

10. Find the missing number:

1, 3, 7, 15, 31, ?

(A) 62  (B) 63  (C) 64  (D) 65

Answer: (B) 63

Explanation:

Pattern: (×2) +1 each time → 1×2+1=3, 3×2+1=7 → next = 31×2+1 = 63

11. Find the next term:

A1, B2, C3, D4, ?

(A) E5  (B) E6  (C) F5  (D) F6

Answer: (A) E5

Explanation:

Alphabet increases by +1 and number increases by +1 each step.

12. Find the missing number:

6, 11, 21, 36, 56, ?

(A) 71  (B) 81  (C) 91  (D) 96

Answer: (C) 91

Explanation:

Differences = +5, +10, +15, +20 → next +25 → 56 + 25 = 81 (Corrected: Option B)

13. Find the next letter pair:

AB, CD, FG, KL, ?

(A) PQ  (B) MN  (C) OP  (D) RS

Answer: (C) OP

Explanation:

Gaps between letters increase: +1, +2, +3, +4 → next +5 → K +5 = P → OP

14. Find the missing number:

11, 13, 17, 19, 23, ?

(A) 25  (B) 27  (C) 29  (D) 31

Answer: (C) 29

Explanation:

Series of prime numbers → next after 23 is 29

15. Find the next letter:

A, Z, B, Y, C, X, ?

(A) D  (B) W  (C) DW  (D) Both A and B

Answer: (D) Both A and B

Explanation:

Pattern alternates from start (A, B, C, D) and end (Z, Y, X, W).

Summary Table

Q.No Answer Concept

1 C Difference pattern

2 C Position pattern

3 C Multiplication series

4 A Reverse alphabet

5 A Perfect squares

6 B Incremental difference

7 A Alphabetic shift

8 C Doubling pattern

9 A Opposite sequence

10 B ×2 +1 pattern

11 A Letter-number mix

12 B Arithmetic difference

13 C Increasing gaps

14 C Prime number series

15 D Alternating pattern