Question 28619
Rex's age = x
Rodney = y


x+y=50
y=50-x (sub)


FIve years ago rex's age = x-5
Five years ago son's age = y-5


3(y-5)=x-5
3y-5=x-5
SUb
3(50-x-5)=x-5
135-3x=x-5
-4x=-140
x=35


y=50-35
y=15


Hence, Rex is 35 years old and his son is 15 years old.
PAul.