Question

show that there is no value of n for which (2^n5^n) ends in 5

Answer 1

let us do it by the method of substitution....let n=2

now 2^2×5^2
4×25
=100...we can observe that it doesnot end it with 5

Answer 2

10^n will always result in multiple of 10.Thus,it will never end in 5....hope it helps you....