What letters will fill the blank?

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

In the following question, select the missing number from the given series.
3, 4, 5, 4, 9, 10, 6, 16, 15, 9, 25, 20, 13, 36, ?

In the following question, select the missing number from the given series.
7, 19, 42, 87, ?

In the following question, select the missing number from the given series.
1357, 3085, 5282, 8026, ?

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

9 , 21, 45, 93, ? , 381

In the following question, select the missing number from the given series.
19, 38, ?, 228, 684, 1368

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

2, 4, 13, 41, 106, ?

Select the missing number from the given responses:

Which number will complete the series?

63, 72, 81, 90, ____, 108