What is the right most non-zero digit of the number 30^2720

What is the right most non-zero digit of the number 302720?

  1. 1
  2. 3
  3. 7
  4. 9

Answer

The right most non-zero digit can be found using pattern method.

301 = 3

302 = 9

303 = 7

304 = 1 

The pattern repeats from here. Since 2720/4 gives the remainder 0, right most non-zero digit will be 1.

The correct option is A.