Tina's father is 7 times as old as Tina. One year ago he was nine times as old as she was. Find the present age of each.
P.S I know the answer I just need an equation
Tina's current age --- x
her dad's current age = 7x
a year ago:
Tina was x-1
her dad was 7x-1
7x - 1 = 9(x-1)
7x-1 = 9x - 9
-2x = -8
x = 4