First solve the given expressions for p, and q
p=15−(3−5)⇒p=15−(−2)⇒p=15+2⇒p=17
and q=(15−5)−3
⇒q=10−3⇒q=7
Clearly, changing the way of associating the numbers in subtraction changes the answer, as subtraction doesn’t have the associative property.
The value of p = 17 and q = 7
Now, subtract p - q
∴p−q=17−7=10