Question

The age Of a father is twice sum Of the ages Of his two children. After 20 years. his age Will equal to the sum Of the ages Of the children. Find the age Of the father.

Answer 1

after 20 year the age of his father is 60
now the age of father 40 and two children age 10 +10=20 duble of his father
after 20 year father age 60 and two children age 30+30=60
equal age of his father

Answer 2

let age of father be x. and let y be sum of ages of his two children. given age of father is twice of this two children
which implies

x= 2 y . ...(1)

after 20 year, given his age will be equal to the sum of ages of the children. which implies

x+ 20= y+ 40....(2)..( this is because each child has aged 20 years, so the sum of the years the 2 children have aged is 40. )

putting x= 2y in (2) we get
2y+20= y+40
=> y= 40-20
=>y=20
now substituting y =20 in equation (1) we get
x= 40
hence age of father is 40.