D + S = 66
2 (S - 9) = D - 9 ... 2 S = D + 9
solve the system for D and S
The sum of the ages of Demetrius and Sonya is 66 years. 9 years ago, Demetrius's age was 2 times Sonya's age. How old is Demetrius now?
1 answer
1 answer