Question

How many five digit number can be formed using the digits 2,3,8,7,5 exactly once such that they are divisible by 125?

___.

Answer 1

Any number is divisible by 125, if the number formed by the hundred's place, ten's place and unit's place is also divisible by 125.
In the digits 2,3,8,7,5. There will be two combinations for hundred, tens and units place i.e. _ _ 375 and_ _ 875.
Hence five digits numbers, which can be formed using

2,3,8,7,5 are 23875,32875,82375 and 28375.