Question

If p is a single digit number (0 - 9) such that p^n – p is always divisible by 5, where n is a natural number, then how many values can p take?

Answer 1

Only 5 is the no. that can fit the conditions. 5 is a no. between 0-9 and 5^n is always divisible by 5. Therefore p can only take 1 value that is 5.