Question

In each of the following question, select the related number from the given alternatives.
$7$ $:$ $42$ $:$ $:$ $9$ $:$ $?$

• A. $64$
• B. $72$
• C. $46$
• D. $80$

Answer 1

The correct option is B $72$

Observing the relation $7:42$

$42=7\times (7-1)$

Similarly the no. that will be related with $9$ will be

$9\times (9-1)=72$

So option $B$ will be correct answer.