Question

Show that there is no value of n for which `(2^n xx  5^n)`  ends in 5.

Answer 1

We can write:
 `(2^n xx  5^n)`  = (2 × 5) n
                       = `10^n`
For any value of n, we get 0 in the end.
Thus, there is no value of n for which `(2^n xx  5^n)` ends in 5.