Find the missing number:
2, 5, 10, 17, 26 ,?

What should come at place of question mark (?) in the following number series?

15 20 50 165 680 ? 

In the following question, select the missing number from the given series.
 129, 126, 123, 120, 117, ?

The series given below contains a sequence of numbers. Identify the incorrect combination: 

56, 54, 58, 49, 66, 34

In how many ways can letter of the word MAILINGS arrange so that M and N always come together? 

In this question, a sequence is given, with one term missing. Choose the correct option from the given options.
10 , 18 , 28 , 40 , ? 

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
15, 26, 48, 81, 125, ?

Select the option that is related t o the third term in the same way as the second term is related to the first term and the sixth term is related to the fifth term.
 24 : 840 :: 27 : ? :: 33 : 1452