Logical Reasoning & Analytical Ability – Number and alphabet series
Assam Public Service Commission (APSC)
Combined Competitive Examination (CCE)
Preliminary Examination – General Studies Paper II (Objective Type, 200 Marks)
Topic: Logical Reasoning & Analytical Ability
Sub-Topic: Number and Alphabet Series
MCQ 1
Find the next number in the series:
2, 4, 8, 16, ?
A. 18
B. 24
C. 32
D. 64
Correct Answer: C
Explanation: Each term is multiplied by 2:
2 × 2 = 4, 4 × 2 = 8, 8 × 2 = 16, 16 × 2 = 32
MCQ 2
Find the missing term:
5, 10, 20, ?, 80
A. 25
B. 30
C. 40
D. 60
Correct Answer: C
Explanation: Each term is multiplied by 2:
20 × 2 = 40
MCQ 3
Find the next number:
1, 4, 9, 16, ?
A. 20
B. 25
C. 24
D. 36
Correct Answer: B
Explanation: Squares of natural numbers:
1², 2², 3², 4², so next is 5² = 25
MCQ 4
Find the missing number:
2, 6, 12, 20, ?
A. 28
B. 30
C. 32
D. 40
Correct Answer: A
Explanation: Pattern: n(n+1)
1×2=2, 2×3=6, 3×4=12, 4×5=20, 5×6= 30 → but sequence adds +4, +6, +8 → next +10
20 + 8 = 28
MCQ 5
Find the next term:
100, 90, 81, 73, ?
A. 66
B. 65
C. 64
D. 62
Correct Answer: B
Explanation: Subtracting decreasing numbers:
−10, −9, −8 → next −7
73 − 8 = 65
MCQ 6
Find the next number:
3, 6, 11, 18, ?
A. 25
B. 26
C. 27
D. 29
Correct Answer: B
Explanation: Differences:
+3, +5, +7 → next +9
18 + 8 = 26
MCQ 7
Find the missing number:
1, 3, 6, 10, ?
A. 13
B. 14
C. 15
D. 16
Correct Answer: C
Explanation: Triangular numbers:
1, 3, 6, 10, 15
MCQ 8
Find the next number:
7, 14, 28, 56, ?
A. 84
B. 112
C. 98
D. 64
Correct Answer: B
Explanation: Each term × 2:
56 × 2 = 112
MCQ 9
Find the missing term:
4, 9, 16, 25, ?
A. 30
B. 35
C. 36
D. 49
Correct Answer: C
Explanation: Squares of even numbers starting from 2²:
2², 3², 4², 5² → next 6² = 36
MCQ 10
Find the next number:
1, 1, 2, 3, 5, ?
A. 6
B. 7
C. 8
D. 9
Correct Answer: C
Explanation: Fibonacci series:
Sum of previous two terms → 3 + 5 = 8
Alphabet Series
MCQ 11
Find the next letter:
A, C, E, G, ?
A. H
B. I
C. J
D. K
Correct Answer: B
Explanation: Skipping one letter each time:
A(+2)C(+2)E(+2)G → I
MCQ 12
Find the missing letter:
Z, X, V, T, ?
A. R
B. Q
C. P
D. O
Correct Answer: A
Explanation: Moving backward by −2 letters:
Z, X, V, T → R
MCQ 13
Find the next term:
A, D, G, J, ?
A. K
B. L
C. M
D. N
Correct Answer: C
Explanation: Each letter +3 positions:
J + 3 = M
MCQ 14
Find the missing letter:
B, E, H, K, ?
A. L
B. M
C. N
D. O
Correct Answer: B
Explanation: +3 letter sequence:
K + 3 = M
MCQ 15
Find the next letter:
A, Z, B, Y, C, ?
A. X
B. W
C. D
D. V
Correct Answer: A
Explanation: Alternating forward and backward:
A↔Z, B↔Y, C↔ X
Mixed Number–Alphabet Series
MCQ 16
Find the next term:
A1, B2, C3, D4, ?
A. E4
B. D5
C. E5
D. F6
Correct Answer: C
Explanation: Alphabet and number both increase by 1 → E5
MCQ 17
Find the missing term:
A, C, F, J, ?
A. N
B. O
C. P
D. Q
Correct Answer: B
Explanation: Letter positions:
1, 3, 6, 10 → next 15 = O
MCQ 18
Find the next number:
2, 5, 10, 17, ?
A. 24
B. 25
C. 26
D. 27
Correct Answer: C
Explanation: Differences:
+3, +5, +7 → next +9
17 + 9 = 26
MCQ 19
Find the missing letter:
M, N, P, Q, S, ?
A. T
B. U
C. V
D. W
Correct Answer: B
Explanation: Pattern: +1, +2 alternately
S + 2 = U
MCQ 20
Find the next number:
81, 27, 9, 3, ?
A. 1
B. 2
C. 0
D. 6
Correct Answer: A
Explanation: Each term ÷ 3
3 ÷ 3 = 1
Advanced Series
MCQ 21
Find the missing term:
1, 4, 13, 40, ?
A. 121
B. 120
C. 123
D. 160
Correct Answer: A
Explanation: Multiply by 3 and add 1:
40 × 3 + 1 = 121
MCQ 22
Find the next letter:
A, B, D, G, K, ?
A. O
B. P
C. Q
D. R
Correct Answer: A
Explanation: Letter gaps: +1, +2, +3, +4 → next +5
K + 5 = O
MCQ 23
Find the next number:
5, 11, 23, 47, ?
A. 93
B. 94
C. 95
D. 96
Correct Answer: C
Explanation: Multiply by 2 and add 1:
47 × 2 + 1 = 95
MCQ 24
Find the missing letter:
C, F, J, O, ?
A. T
B. U
C. V
D. W
Correct Answer: B
Explanation: Letter jumps: +3, +4, +5 → next +6
O + 6 = U
MCQ 25
Find the next number:
6, 15, 28, 45, ?
A. 60
B. 63
C. 66
D. 70
Correct Answer: C
Explanation: Differences:
+9, +13, +17 → next +21
45 + 21 = 66
MCQ 26
Find the next letter:
D, H, L, P, ?
A. R
B. S
C. T
D. U
Correct Answer: C
Explanation: +4 letter pattern:
P + 4 = T
MCQ 27
Find the missing number:
1, 8, 27, 64, ?
A. 100
B. 121
C. 125
D. 216
Correct Answer: C
Explanation: Cubes of natural numbers:
1³, 2³, 3³, 4³ → next 5³ = 125
MCQ 28
Find the next term:
AZ, BY, CX, DW, ?
A. EV
B. EU
C. FV
D. FW
Correct Answer: A
Explanation: First letter forward, second backward
D→E, W→V → EV
MCQ 29
Find the missing number:
2, 3, 5, 8, 13, ?
A. 18
B. 20
C. 21
D. 24
Correct Answer: C
Explanation: Fibonacci pattern:
8 + 13 = 21
MCQ 30
Find the next letter:
A, C, F, J, O, ?
A. T
B. U
C. V
D. W
Correct Answer: A
Explanation: Letter positions:
1, 3, 6, 10, 15 → next 21 = T
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