What is the missing number in the series: 2, 6, 12, 20, ?, 42

B. 32

Complete the series: A, D, G, J, ?

A. M

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

D. P

Complete the series: z, x, v, t, ?

A. R

Find the missing letter in the series: a, e, i, o, ?

A. U