What is the next number in the series: 10, 20, 30, 40, ?

B. 50

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

A. 160

What number should replace the question mark in the series: 3, 6, 11, 18, ?, 38

B. 26

What is the missing number in the series: 2, 5, 10, 17, ?, 37

B. 28

Identify the missing number in the series: 5, 10, 20, 40, ?, 160.

A. 80