A father is four times the age of his son. In four years’ time the father will be three times the age of his son. How old is the father now

Let the son's age now  = x   ....  then the father's age is 4x

And in four years, we have

3(x + 4) = 4x + 4   simplify

3x + 12 = 4x + 4

x = 8   and that's the son's age now

And the father's age now is 4x = 4(8)  = 32