What is the remainder

GRE Quant Problem Solving
1

What is the remainder when 25^25 is divided by 9?

I can’t seem to identify the remainder pattern.

5^1 = 5; remainder when 5/9 = 5
5^2 = 25; remainder = 7
5^3 = 125; remainder = 8
5^4 = 625; remainder = 4
5^5 = 3125; remainder = 2
5^6 = 15625; remainder = 1

…
Help?

2

Try 5^7 and 5^8.

4

Wow ok, ok seems like the pattern is 5,7,8,4,2,1. That is quite a long remainder pattern.

1 Like