Home  / Verbal Reasoning  / Series Completion  / Number Series
Number Series
Alphabet Series
Letter Series

Identify the missing number in the series: 3, 7, 13, 21, ?, 61

Answer: A. 31
The differences between terms are increasing by 2: 4, 6, 8, 10. The missing term is 21 + 10 = 31.
Posted in:  Number Series -  Series Completion -  Verbal Reasoning