Question

7. Find the number of powers of 20 in 100!​

Answer 1

20 = 5 * 4

thus the no. of times 5 & 4 will appear in 100! will be the power of 20 in 100!..

but it is well understood that no. of 5's are always lesser than 4 in 100! ...

thus we only need to calculate no. of 5's...

= (100/5)+(100/25)

=20+4

=24 is d power of 20.

it will help you