Math Question?

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A bag contains 5 red marbles, 10 blue marbles, and 20 green marbles.
If two marbles are taken out at random, one by one, without replacement, what is the probability that they are both blue?

2007-09-16 14:58:26 · 1 answers · asked by vanilla_latte62 1 in Science & Mathematics ➔ Mathematics

1 answers

There are 35 marbles (5 + 10 + 20)
The chance that the first marble is blue is 10/35 = 2/7

Now there are only 34 marbles left and only 9 of them are blue, so the chance of the second marble is 9/34

Multiply the two chances together
2/7 * 9/34 = 18/238 = 9/119

2007-09-16 15:10:14 · answer #1 · answered by Steve A 7 · 0⤊ 0⤋