Answer:
Step-by-step explanation:
x = father's age
y = son's age
Nowadays:
3x = y
5 years ago:
4(x - 5) = y - 5
4x - 20 = y - 5
4x = y + 15
I hope I've helped you.
The answer to your problem is A because you must add them altogether but i might be wrong im just trying to help you out