Question

Replace the ? with appropriate number in the given series.

$25,43,44,53,?,72$

• A. $55$
• B. $63$
• C. $65$
• D. $71$

Answer 1

The correct option is D $71$

The differences in this series are in order as $18,1,9,18,1,9$

$25+18=43$

$43+1=44$

$44+9=53$

Then $53+18=71$

$71+1=72$

$72+9=81$

and so on....

Hence $71$ replaces question mark.