Consider an experiment in which two marbles are drawn from an urn at the same time. If the urn contains 3 white marbles and 2 red marbles, what is the probability that both marbles will be white? (I appreciate the answers, but someone respond back with an explanation to the answer)
2006-11-28 10:16:40 · 4 answers · asked by Nathan D 1 in Science & Mathematics ➔ Mathematics
The probability that the first marble will be white is 3 / 5.
If we draw again without replacing the first marble, the probability that the second marble will also be white is 2 / 4.
3/5 * 2/4 = 3/10.
There is a 30% chance that both marbles will be white.
2006-11-28 10:19:01 · answer #1 · answered by hokiejthweatt 3 · 0⤊ 0⤋
Okay, 3 white marbles and 2 red marbles. Thus, there are 5 total marbles. Choosing both marbles at the same time is the same as choosing both marbles separately without replacement. The first time, you have 3 chances out of 5 to pick a white marble. The second time, you have 2 chances out of 4 to pick a white marble. Multiply your results together, and you have 6 chances out of 20 to pick a white marble, or 3 chances out of 10. So, you probability is 3/10.
2006-11-28 18:25:46 · answer #2 · answered by Dan 3 · 0⤊ 0⤋
To figure out the "odds" of getting success (2 white marbles) you need to determine how many ways you can be successful and divide this by how many possible ways you can draw out two marbles.
If your white marbles had letters on them (A, B, C) - there would be only 3 possible combinations (or ways) you can pull two of them. You are either going to get AB, or AC, or BC. 3 successes possible
Now if all of your marbles had letters on them (A,B,C,D,E), how many ways can you pull two marbles out? AB, AC, AD, AE, BC, BD, BE, CD, CE, DE - there are 10 possible ways to draw out two marbles.
So the probability is 3 divided by 10, 3/10ths, or 30%.
Good luck - I prefer to pull out M&Ms, but then some get eaten and it changes the results.
2006-11-28 18:41:10 · answer #3 · answered by sandybear 1 · 0⤊ 0⤋
Whats the probability the first one is white? 3/5, since there are 3 white out of 5 total.
Now, after we have chosen a white, there are 2 whites, 2 reds. Whats the probability the next one is white? 2/4, so there are 2 whites out of 4 total.
So 3/5 * 2/4 = 3/10.
2006-11-28 18:19:07 · answer #4 · answered by stephen m 4 · 0⤊ 0⤋