What letters will fill the blank?

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

Select the number missing from the given number series.

4, 9, 20, 44, ?

Select the number missing from the given series.

3, 12, ___, 21612

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

93, 100, 107, 114, ?, 128

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

23, 24, 26, 27, 29, ?

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

131, 138, 145, 152, ?, 166

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

19, 21, 25, 27, 31, ?

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

107, 104, 100, 95, ?, 82

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

11, 14, 19, 22, 27, ?