What number can replace the question mark in the series 1, 4, 7, 13, 22, 37, 61, 100, ?

A163 ✓ Correct

B161

C171

D173

Correct answer: (A) 163

Explanation

The next term is 163.

differences are 3, 3, 6, 9, 15, 24, 39.

each gap = sum of the two before it.

next gap = 24 + 39 = 63.

100 + 63 = 163.

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