Present ages:
Gustav's ages: x
His father: 7x
Ages one year ago:
Gustav's age: x - 1
His father: 7x -1
Equation:
9(x-1) = 7x - 1
9x - 9 = 7x - 1
9x - 7x = 1 + 9
2x = 10
2x/2 = 10/2
x = 5
ANSWER: Gustav's present age is 5 years.
Check:
Gustav's father is seven times as old as he is.
Gustav = 5 years old
His father = 7 (x) = 35 years old
