Grandpa's age is 75 years
Seven times the age of junior = age of grandpa + 9 jears = 75 + 9 = 84 years
Hence, the age of junior will be 84 / 7 = 12 years. (Since 84 is seven times his age, you have to devide by seven).
--> Junior is 12 years old.
I hope I've been helpful, MarkV
