11. 

3, 4, 7, 7, 13, 13, 21, 22, 31, 34, ?

A. 42
B. 43
C. 51
D. 52

12. 

198, 194, 185, 169, ?

A. 92
B. 112
C. 136
D. 144

13. 

2, 3, 5,7,11,?, 17

A. 12
B. 13
C. 14
D. 15

14. 

6, 12, 21, ?, 48

A. 33
B. 38
C. 40
D. 45

15. 

Which term of the series 5, 10, 20, 40, ..... is 1280?

A. 10th
B. 9th
C. 8th
D. None of these