Question

4 years ago a father was 6 times as old as his son.10 years later the father is 2 and a half times as old as his son.find their ages

Answer 1

Four years ago :

Son's age=x

Father's age =6x

Present age:

Sons age = x+4

Fathers age =6x+4

10 years later :

Son's age =x+14

Father's age =6x+14; given fathers age is 5/2 times sons age(in this case only)

So we can write:

6x+14=5/2 (x+14)

6x+14=(5x+70)/2

12x+28=5x+70

7x=42

X=6 (this is son's age 4 years ago)

So his present age will be 10 years and fathers age will be 40 years