Let's denote Cindy's age which is unknown with X We know that Cindy's age is 3 times her age 6 years ago. 6 years ago Cindy's age was the present age (X) - 6 : X-6 The fact that the present age is 3 times her age 6 year ago can be written as: 3*(X-6) So, finally: X=3*(X-6)
