Question

Find remainder when 3^50 +1 is divided by 10

Answer 1

3^1=3

3^2=9

3^3=27

3^4=81

3^5=243.......

We see that 3 has a cyclicity of 4

So when 50 is divided by 4, remainder is 2

Therefore the unit digit of 3^50 is 9.

According to the question,

In 3^50 +1, as 9+1=10, the unit digit will be always 0. So the number will always be divisible by 10.

So the remainder is 0. (Ans)

Hope it helps.....