Question

3 years ago the sum of ages of father and his son was 54 years. After 3 years the father's age will be double age of son's age after 9 years. Find the present ages of father and son.​

Answer 1

Father is 41 years old and son is 13 years old.

Explanation:

Set father is x years old, and son is y years old 3 years ago.

x+y=54

x+3=2(y+9) x+3=2y+18

x+y=54

-) x-2y=15

---------------------

3y=39 y=13, x=41

Answer 2

x+y= 54

x+3= 2(y+9) - multiply the bracket by 2

x+3 = 2y+18

x+3-3= 2y+18-3

x= 2y+15

x-2y= 15

x+y= 54

x-x-2y+-y= 15-54

-2y-y= - 39

-3y=-39

Divide by -3 for -3y and -39

-3y/-3= -39/-3

y = 13 ( son)

Use substitution method to find x

x+y= 54

x+13= 54

x+13-13= 54-13 ( moving +13 to -13 to the other side)

x= 41 ( father)

Answer is father is 41 years old -x

Answer is father is 41 years old -xSon is 13 years old -y