mary has a bag that contains 6 green marbles, 9 red, and 6 blue, without looking she draws a marble?

9/21 x 6/21

Chance of a red marble times chance of a blue marble

54/441

12.3%

There are 21 marbles in total, so the probability of drawing a red marble on the first draw is 9/21. She puts this back to make a bag of 21 marbles again, and then tries to draw a blue marble. The probabiltiy of that is 6/21.

So to find the probability (which isn't the same as a percent) that Mary draws a red marble first and a blue marble second, multiply the two probabilities:

9/21 * 6/21 = (3/7) * (2/7) = 6/49.

3/7ths of the time she'll draw a red marble and 2/7ths of the time she'll draw a blue marble. When multiplied, it's 6/49ths of the time she'll draw a red marble then a blue marble... or about 12.24% of the time.

2/7*3/7= 6/49

That depends..I know it's not good to put all your marbles in one basket..or is that eggs.