Ken had a number of colored marbles in a bag. 1/4 of the marbles were red, 2/3 of the remaining marbles were blue, and the rest were yellow. Given that there were 120 red and yellow marbles altogether, how many marbles were there in the bag?

Answer 1

red = .25
blue = 2/3 * .75 = .5
yellow = .25

I think you can take it from there