The correct option is A 15
First we notice the desired quantity (p - q) on the L.H.S of the equation. We solve for this expression by subtracting 8 from both sides :
5(p−q)+8−8=7−8
5(p−q)=−1
Next dividing both side by 5
5(p−q)=−1
(p−q)=−15
Therefore, the value of (q - p) =15