Need help understanding a probability question

This is on a past paper and I need help as I don't know how to approach it?

Robin is firing arrows at a target.
The probability that he hits his target on his xth attempt is
x+2
------
x+3

For example probability (hit on his 5th attempt)= 7/8

a) work out the probability that he hits the target with both his 1st and 2nd attempts.

b) work out the probability that he hits the target exactly once on his first two attempts.