Infosys Number series Questions with Answers

1. Choose the correct alternative that will continue the same pattern and fill in the blank spaces:
2, 3, 5, 7, 11, (….), 17
A. 12
B. 13
C. 14
D. 15
Answer: Option B
Solution:
Clearly, the given series consists of prime numbers starting from 2. The prime number after 11 is 13. So, 13 is the missing number

2.522 1235 2661 4800 7652 11217 ?
A. 15495
B. 16208
C. 14782
D. 16921
Answer: Option A

3.What is the 8th term in the series 1, 4, 9, 18, 35, 68, . . .
A.262
B.148
C.342
D.112
Answer: Option c
Explanation:
1, 4, 9, 18, 35, 68, . . . The pattern is 1 = 21 – 1 4 = 22 – 0 9 = 23 + 1 18 = 24 + 2 35 = 25 + 3 68 = 26 + 4 So 8th term is 28 + 6 = 262

4. 8 11 21 15 18 21 22
A.25 18
B.25 21
C.25 29
D.24 21
E.22 26
Answer: Option B

5. Look at this series: 2, 6, 18, 54, … What number should come next?
A.108
B.148
C.162
D.216
Answer: Option C

6. Look at this series: F2, __, D8, C16, B32, … What number should fill the blank?
A.A16
B.G4
C.E4
D.E3
Answer: Option C

7. Look at this series: V, VIII, XI, XIV, __, XX, … What number should fill the blank?
A.IX
B.XXIII
C.XV
D.XVII
Answer: Option D

8.Look at this series: 4, 7, 25, 10, __, 20, 16, 19, … What number should fill the blank?
A.13
B.15
C.20
D.28
Answer: Option A

9. 6 10 14 18 22 26 30
A.36 40
B.33 37
C.38 42
D.34 36
E.34 38
Answer: Option D