Which of the following numbers will replace the question mark (?) and complete the given number series?
15, 19, 21, 25, 27, ?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 31.
15 + 4 = 19; 19 + 2 = 21; 21 + 4 = 25; 25 + 2 = 27; 27 + 4 = 31