Question

Five years ago a man was seven times as old as his son. five years hence, the father will be three times as old as his som. find their present ages.

Answer 1

at present
son age = x years
father age = y years
5yrs ago,

son age = x-5
father age =y-5
y-5 = 7(x-5)

y-5 = 7x-35------(1)

after 5 yrs

son age = x+5
father age = y+5
y+5 = 3(x+5)

y+5= 3x+15------(2)
subtract (2) from (1)
-10 = 4x-50
-10+50=4x
40 =4x

4x =40
x=40/4
x=10
at present
son age = x= 10 year
substitute x=10 in (2)
y+5=3(10)+15
y=30+15-5
y=40
father age = y =40 years