A bag contains 4 blue, 5 green and 3 red marbles. How many green marbles must be added to the bag so that at least 79 percent of the marbles are green?
22 green marbles.
To solve, let x be the number of marbles added.
simplifying, we see that
so x is at least 22.
If we put this back into the original problem, there would be 27 green marbles and 34 marbles total.
27/34 is about 0.79411, which is slightly above 79%.