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from the bag. she puts the marble back in the bag and then draws another marble out of the bag. What is the probability that Mary with draw a red marble followed by a blue marble?

2007-03-26 10:47:30 · 5 answers · asked by onyx 2 in Education & Reference Homework Help

5 answers

9/21 x 6/21
Chance of a red marble times chance of a blue marble

54/441
12.3%

2007-03-26 10:53:14 · answer #1 · answered by beavis n butthead 2 · 2 1

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.

2007-03-26 11:02:10 · answer #2 · answered by Anonymous · 0 1

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.

2007-03-26 10:54:10 · answer #3 · answered by ? 2 · 1 0

2/7*3/7= 6/49

2007-03-26 11:34:56 · answer #4 · answered by erin r 2 · 0 1

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

2007-03-26 10:50:39 · answer #5 · answered by ? 3 · 0 2

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