Question

"I am five times as old as you were, when I was as old as you are", said a man to his son. Find out their present ages, if the sum of their ages is 64 years ?

The answer was son=24 and man=40 years, but if man = 24 years then son = 8 years which is not 5 times as in question....

Answer 1

The question meant that he is five times his son's age when he was of his age.

Father's present age=x                                   Son's present age=y

Now father tells that he was of y age and his son was of age y-(x-y).
So x+y=64
     x=5[y-(x-y)]
     x=5[y-x+y]
     x=5[2y-x]
     x=10y-5x
     x+5x=10y
     6x=10y
     x=10y/6
10y/6+y=64
 10y/6+6y/6=64
16y=64*6 
16y=384
 y=384/16
 y=24=Son's age

x+24=64
x=64-24
x=40=Father's age

y-(x-y)=24-(40-24)
          =24-16
          =8

Your doubt=8(son's previous age)
             40=5(8)
             40=40