Question

Find the term to replace the question mark in order to complete the series.

$1,2,10,4,3,14,9,5,?$

• A. $19$
• B. $21$
• C. $17$
• D. $18$

Answer 1

The correct option is D $18$

The given sequence comprises of three sequences
$1,4,9,16$ (Square of $1,2,3,4$)
$2,3,5,7$ (Prime number series)
$10,14,18,22$ (Common difference 4)
The missing number belongs to series number three, so it is $18$.