How do i write out an equation for this?

Question

The sum of the ages of Courri and Gail is 74 years. 11 years ago, Courri's age was 3 times Gail's age. How old is Courri now?

Answer 1

Couri Gail

Now: C G

11 yrs ago: C - 11 = 3(G - 11)

Also C + G = 74 so G = 74 - C

C - 11 = 3G - 33 Substituting: C - 11 = 3(74 - C) - 33

C - 11 = 222 - 3C - 33

4C = 222 - 33 + 11

4C = 200

C = 50 yrs old; G = 24 yrs old now.

11 years ago C was 39 and G was 13 (3:1 ratio)