Question

The exponent of $2$ in $x=20\times 19\times 18\times ...\times 11$ is

• A. 8
• B. 10
• C. 12
• D. 14

Answer 1

The correct option is B 10

Only even numbers will be divisible by $2$,
$=>20,18,16,14,12$
$=>4,2,(4,4),2,4$
$=>2^{2+1+4+1+2}$$=2^{10}$
exponent = $10$
Hence, option 'B' is correct.