What letters will fill the blank?

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

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

57, 69, 81, 93, ?, 117

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

19, 25, 32, 38, 45, 51, ?

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

4, 9, 16, 25, 36, ?

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

10, 12, 14, 16, 18, ?

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

11, 13, 16, 18, 21, ?

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

3/5, 1.4, 11/5, ? , 19/5, 4.6

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

1, 0.25, 1/9, ? , 0.04, 1/36

In the following question, one term in the number series is wrong. Find out the wrong term?

5, 10, 40, 80, 320, 550, 2560