Question

Q 1: Dad is seven times as old as his son. 10 years later, he will be three times as old as his son. Find their ages.give me step wise answer

Answer 1

Let the age of son be x the the age of dad will be 7x.
After 10 years he will be three times as old as his son
that is  7x+10= 3(x+10)
    7x+10= 3x + 30
     7x-3x= 30 - 10
 4x = 20
x = 5
So, age of son is 5 years and age of father is 35 years

Answer 2

let s be age of son
d=7*s
with increase in years i.e,10 even the son's increases
d+10=3(s+10) 
d=7s
7s+10=3s+30
7s-3s=20
4s=20
s=5
d=7s
d=7*5
d=35