Numbers

The last digit of the number 32015 is

  1. 1
  2. 3
  3. 5
  4. 7

Solution

The cyclic frequency of number 3 is 4. Last digit comes in iteration of 4 numbers: 3, 9, 7 and 1.

31 = 3

32 = 9

33 = 27

34 = 81

35 = 243

Cyclic frequency means that the last digit repeats after every fourth power. Last digit of:

34n+1 is 3

34n+2 is 9

34n+3 is 7

34n+4 is 1

Now, you have to find remainder when 2015 is divided by 4. The remainder is 3.

2015 = 4n + 3

Last digit will be 7.

Correct option is D.