Question 663456
Judy, who is 17 years old, has a grandmother 77 years. How many years ago was Judy's grandmother 6 times as old as Judy? 
let x=years ago when grandmother was 6 times as old as judy
17-x=judy's age x yrs ago
77-x=grandmother's age x yrs ago
..
77-x=6(17-x)
77-x=102-6x
5x=25
x=5
years ago when grandmother was 6 times as old as judy=5