Question

Can someone please help me solve this?!

Answer 1

At the start:

Ryan/Audrey = 2x/7x

Now:

Ryan/Audrey = (2x + 20)/(7x - 80) = 1/3

(2x + 20)/(7x - 80) = 1/3

3(2x + 20) = 7x - 80

6x + 60 = 7x - 80

x = 140

Audrey started with 7(140) = 980 marbles.