Question 1178816
The combined age of a father and his son
are 36.In seven years the father will
be four times as old as his son.

let father,s age be x
son,s age be y

combined age of a father and his son
are 36.

x+y=36---------------(1)

In seven years the father will
be (x+7) years 
son's age will be( y+7) years

father four times as old as his son
(x+7) = 4(y+7)
x+7 =4y+28
x-4y=21----------------(2)

5y=15
y=3
x=33

father,s age 33 years
son,s age  3 years