What is their age now

Question

Mr b and his sons age combined age is 30. 4 years ago mr b was 5 times as old as his son. How old are they now

Answer 1

Let x = Mr. 's age

Let y = the son's age

 x  + y = 30      x = 30 - y

x-4 = Mr. B's age four years ago

y-4 = son's age four years ago

x-4 = 5(y-4)

x-4 = 5y - 20

30 - y - 4 = 5y - 20

46 = 6y

y = 7 2/3 years

x = 30 - y = 30 - 7 2/3

x = 22 1/3 years