PrepSwift: Words to Algebra I (2 of 3)

GRE Quant Problem Solving
1

For question 2 of 3:

Dion and Ripley are currently D and R years old. After 20 years, Dion will be four times as old as Ripley. Which equation best describes their ages 20 years from now?

I thought first to make their ages in 20 years.

D + 20
R + 20

Then, Dion is four times as old as Ripley.

4(D+20) = R+20

PrepSwift has

D+20 = 4(R+20) as the answer. Wouldn’t this have Riply as being four times as old. Can you help clarify why the four is on the RHS?

2

In this case, Ripley is older. Try your equation above with an example.