In following number series, two terms have been put within brackets. Choose the appropriate option - Look at this series: 2, 4, 6, 8, 10, . . . What number should come next ?

B. 12

In following number series, two terms have been put within brackets. Choose the appropriate option - Look at this series: 40, 40, 47, 47, 54, . . . What number should come next?

C. 54

In following questions, one term in number series is incorrect. - Find out the incorrect number 3, 2, 8, 9, 13, 22, 18, 32, 23, 42

B. 9

In following questions, one term in number series is incorrect. - Find out the incorrect number 3, 7, 15, 39, 63, 127, 255, 511

B. 39

In following question, a number series is given with one term missing. Choose the correct alternative that will same pattern and fill in the blank spaces. - 2, 3, 5, 7, 11, x, 17

B. 13