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13 Nov 2010, 10:04
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There are 5 different coloured balls in a bag. A ball is chosen and replaced 4 times. What is the probability that:
all the balls chosen are different colours?
2 of the balls are the same colour?
3 of the balls are the same colour?
all the balls are the same colour?
Working out the all same and all different is not too hard but is there a quick way to do the other parts without drawing the 625 branch tree diagram?
all the balls chosen are different colours?
2 of the balls are the same colour?
3 of the balls are the same colour?
all the balls are the same colour?
Working out the all same and all different is not too hard but is there a quick way to do the other parts without drawing the 625 branch tree diagram?
Ellipse
Joined: 16 Oct 2010
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Concentration: Finance, Entrepreneurship
Schools: INSEAD Jan '13 Kellogg 1YR '15 Sloan '16 IE '15
GMAT 1: 700 Q49 V35
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14 Nov 2010, 00:12
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greed1
Hi I was wondering if anyone knows how to work this question out:
There are 5 different coloured balls in a bag. A ball is chosen and replaced 4 times. What is the probability that:
all the balls chosen are different colours?
2 of the balls are the same colour?
3 of the balls are the same colour?
all the balls are the same colour?
Working out the all same and all different is not too hard but is there a quick way to do the other parts without drawing the 625 branch tree diagram?
There are 5 different coloured balls in a bag. A ball is chosen and replaced 4 times. What is the probability that:
all the balls chosen are different colours?
2 of the balls are the same colour?
3 of the balls are the same colour?
all the balls are the same colour?
Working out the all same and all different is not too hard but is there a quick way to do the other parts without drawing the 625 branch tree diagram?
I would like to give it a try.
1) All of the balls cosen are of different color
P = 5/5 * 4/5 * 3/5 * 2 /5 = 24/125
2) p = 5/5 * 1/5 * 4/5 * 3/5 * 4C2 = 72/125
3) p = 5/5 * 1/5 * 1/5 * 4/5 * 4C3 = 16/125
4) p = 5/5 * 1/5 * 1/5 * 1/5 = 1/125
14 Nov 2010, 02:28
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syog
greed1
Hi I was wondering if anyone knows how to work this question out:
There are 5 different coloured balls in a bag. A ball is chosen and replaced 4 times. What is the probability that:
all the balls chosen are different colours?
2 of the balls are the same colour?
3 of the balls are the same colour?
all the balls are the same colour?
Working out the all same and all different is not too hard but is there a quick way to do the other parts without drawing the 625 branch tree diagram?
There are 5 different coloured balls in a bag. A ball is chosen and replaced 4 times. What is the probability that:
all the balls chosen are different colours?
2 of the balls are the same colour?
3 of the balls are the same colour?
all the balls are the same colour?
Working out the all same and all different is not too hard but is there a quick way to do the other parts without drawing the 625 branch tree diagram?
I would like to give it a try.
1) All of the balls cosen are of different color
P = 5/5 * 4/5 * 3/5 * 2 /5 = 24/125
2) p = 5/5 * 1/5 * 4/5 * 3/5 * 4C2 = 72/125
3) p = 5/5 * 1/5 * 1/5 * 4/5 * 4C3 = 16/125
4) p = 5/5 * 1/5 * 1/5 * 1/5 = 1/125
The right method. Your answers add up to 113/125, so what would account for the remaining 12/125?
