There are 28 marbles in the box. There are 12 red marbles, 10 blue marbles, and 6 yellow marbles. What percent of the marbles are NOT yellow?

There are 28 marbles in the box. Some are red (12), others are yellow (6) and others are blue (10).

If in this box there 28 marbles and 6 of them are yellow, we substract to get the quantity of marbles that aren't yellow: 28-6 = 22

So 22 of the 28 marbles aren't yellow: 22/28, which we can simplify dividing the numerator and denominator by 2: 11/14

i think it would be 42cm