Question

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

Answer 1

We can write:

(2ⁿ × 5ⁿ) = (2 × 5)ⁿ

= 10ⁿ

For any value of n, we get 0 in the end.

Thus, there is no value of n for which (2ⁿ × 5ⁿ) ends in 5.