Combinatorics combined with Probability

If the integers $P$ and $Q$ are chosen at random between the numbers 1 and 100 inclusive with repetition, and the probability that with these chosen numbers, the value of $7^P + 7^Q$ is divisible by 5 is $\dfrac AB$ , where $A$ and $B$ are coprime positive integers.

Find $5(A+B)+7$ .