1. 1, 3, 2, 5, 3, 7, 4, 9, 5, 11, 6, ?

a) 10

b) 11

c) 13

d) 9

Explanation: Two series are intermixed. 1, 2, 3, 4, 5, 6 and 3, 5, 7, 9, 11. Hence, the next term should be 13. So option (c) is the answer

2. 1, 4, 27, ?

a) 256

b) 3125

c) 2425

d) none of these

Explanation: The general term of the series is n

^{n}. Hence, the next term in the series would be 4

^{4}= 256. Option (a) is the answer.

3. What is the next term in the following series?

ABE, BCF, CDG, DEH, EFI, ______

a) FGK

b) FGJ

c) FGL

d) none of these

Explanation: The next term in the series would be FGJ. Hence, option (b) is the answer

4. What is the next term in the following series?

ZYXWTSRQNMLK

a) I

b) G

c) H

d) J

Explanation: The given series starts with the last 4 alphabets of the English language and then gives a breakof 2 alphabets, followed by the next four alphabets and so on. Hence, the next term in the series would be H (after skipping J and I). So option (c) is the answer

5. What is the sum of infinite terms of the given series?

\[4+4¥4^{1/2}+4¥4^{1/2}¥4^{1/4}+ \] ______ .

a) 12

b) 16

c) 64

d) none of these

Explanation: On close observation of the series you will realise that every subsequent term reduces in value from the previous term. Hence, by estimating values we can estimate that the sum of this series to infinite terms would be 16. The correct answer is option (b).

6. What is the next term in the following series?

1, 4, 3, 9, 5, 16, 7, 25, 9, 36, 11, ?

a) 64

b) 49

c) 48

d) 55

Explanation: Two series are intermingled with each other as 1, 3, 5, 7, 9, 11 and 2

^{2}, 3

^{2}, 4

^{2}, 5

^{2}, 6

^{2}. Hence, the next term in the series would be 7

^{2}= 49, so the correct answer is option (b)

7. Calculate the sum of the series

1 + 1/4 + 1/16 + ______.

a) 3/4

b) 4/3

c) 2

d) none of these

Explanation: Infinite GP with common ratio 1/4. Hence, Sum to infinity = 1/(3/4) = 4/3. Answer is option(b).

8. Calculate the missing term.

625, 125, ?, 5, 1

a) 1/5

b) 1

c) 5

d) none of these

Explanation: GP with common ratio 1/5. Hence, option (d) is correct.

9. Obtain the missing term.

300, 296, 287, 271, ?, 210

a) 246

b) 250

c) 244

d) none of these

Explanation: The series follows the logic of –4, –9, –16 and hence the missing term must be 271 – 25 = 246. So option (a) is correct.

10. Obtain the missing term.

12, 15, 19, ?, 30, 37

a) 35

b) 34

c) 37

d) 24

Explanation: The series follows the logic of +3, +4, +5, +6 and +7. Hence, the missing term would be 19 +5 = 24. So option (d) is the correct answer.