I am having difficulty figuring out how the answer to this question is 40 per the solution on the gmat practice test. I set up the ratio 5x:3x... I then set up the equation of 7/5= x/10+x to come up with X, but that is where I am stuped..Help please!!
Here is the question:
The number of stamps that kaye & Alberto had were in the ratio of 5:3 respectively. After Kaye gave Alberto 10 of her stamps the ratio Kaye had to the number Alberto had was 7:5. As a result of the gift, Kaye had how many more stamps than Alberto?
The choices were : A-20, B-30, C-40, D-60, E-90