What letters will fill the blank?

Z, X, V, T, R, __,__

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.

4, 9, 25, 64, 169, ?

In the following question, select the missing number from the given series.

43, 44, 46, 47, 49, 49, 50, ?

In the following question, select the missing number from the given series.

12, 15, 19, 24, 30, ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.
19, 29, 40, 44, ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

7, 49, 343, ?

A series is given with one term missing. Choose the correct alternative from the given ones that will complete the series.

18, 25, 34, 45, ?

In the following question, select the missing number from the given series.

28, 30, 36, 48, ?, 98, 140

A series is given, with one number missing. Choose the correct alternative from the given ones that will complete the series.

72, 65.7, ? , 53.1, 46.8