# Thread: Percentage and ratio

1. ## Percentage and ratio

There were some blue marbles and white marbles in a bag. If 70 blue marbles were to be removed from the bag, the ratio of the number of blue to white marbles would be 3:4. If 112 white marbles were to be removed from the bag instead, the ratio of the number of blue marbles to the number of white marbles would be 8:7. When 48 more blue marbles were to be added into the bag, what percentage of all the marbles would be blue marbles?

2. ## Re: Percentage and ratio

Originally Posted by fleurdel
There were some blue marbles and white marbles in a bag. If 70 blue marbles were to be removed from the bag, the ratio of the number of blue to white marbles would be 3:4. If 112 white marbles were to be removed from the bag instead, the ratio of the number of blue marbles to the number of white marbles would be 8:7. When 48 more blue marbles were to be added into the bag, what percentage of all the marbles would be blue marbles?
The answer is 100(X + 48)/(X + 48 + Y), where X and Y are given by:

(X - 70)/Y = 3/4 .... (1)

X/(Y - 112) = 8/7 .... (2)

Part of your job is to figure out what X and Y represent and where these two equations have come from. The other part is to solve equations (1) and (2) for X and Y.