What is the missing number in the series: 100, 90, 80, 70, ?, 50

A. 60

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

D. P

Complete the series: B, D, F, H, ?

D. I

What is the next letter in the series: M, N, O, P, ?

A. Q

What letter comes next in the series: d, g, j, m, ?

A. P