Z, Y, X, W, ?

A. V

What is the missing term in the series: 10, 20, 40, 80, ?, 320

A. 160

Complete the series: a, c, e, g, ?

B. H

What is the next letter in the series: A, C, E, G, I, ?

B. J

Identify the missing letter in the series: Z, X, V, T, ?

A. R