the age of a man is three times the sum

Question

the age of a man is three times the sum of the ages of his two sons. five years hence his age will be double of the sum of the ages of his sons the fathers present age?

 

let one boy age x

other boy age y

father age 3(x+y)

 

 

5 year hence

father age =2(3x+3y)

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

 

father age =x+y

boy=3(x+y)

3(x+y)=x+y

x=(x+y-3y)/3

 

2(x+y+10)=3x+3y

2((x+y-3y)/3+y+10=3((x+y-3y)/3)+3y

how to solve this problem by using two variable. please tell me where did i wrong please explain me

           

Answer 1

Under 5 year hence

father age (3x + 3y) + 5

 

(3x + 3y) + 5 = 2(x + 5 + y + 5)

3x + 3y + 5 = 2x + 2y + 20

x + y = 15                      this is sum of sons' age

 

Father is 3 times that sum, or 45.