what is the probability you select 2 green marbles?
November 22nd, 2009 | by admin |A bag contains 4 red marbles. 4 blue marbles, and 6 green marbles. Half of each color are small marbles, and half are big marbles. Then you randomly select 3 marbles.
What is the probability you select 2 green marbles?
What is the probability you will select all three of the same color?
3 marbles can be chosen out of 14 in 14C3 = 364 ways.
2 green out of 6 can be chosen in 6C2 = 15 ways
The other can be chosen from the remaining non-green 8 in 8C1 = 8 ways.
P(2 green, 1 other ) = (6C2)(8C1) / (14C3) = (15)(8) / 364 = 120/364 = 30/91 ways.
P(3 greens) = 6C3 / 14C3 = 20/364
P(3 reds) = 4C3 / 14C3 = 4 / 364
P(3 blues) = 4C3 / 14C3 = 4 / 364
P(all 3 of same color) = (20+4+4) / 364 = 28/364 = 1/13
6 Responses to “what is the probability you select 2 green marbles?”
By Mojo S on Nov 22, 2009 | Reply
Green- 3/7
All same color-NO IDEAR lol sry
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meeeeeee
By Jennivive on Nov 23, 2009 | Reply
well add them together 4+4+6 14
6 out of the fourteen are green, so 6 out of 14
so then you put it into lowest terms, 3:7
all three of the same color?
3 out of fourteen? im not sure
hope that helped, but im not positive, haven’t taken that since grade seven!
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By DrLove on Nov 23, 2009 | Reply
that depends do you select 1 then put it back then select another. or select all 3 at once.
3/7 * 5/13 = 15/91 * 2/3 30/273 = 10/91 chance getting 2 green marbles.
6/14 * 5/13 * 4/12 = 120/1284 10/107 chance of getting 3 green marbles.
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By Patty is da bomb like tick tick on Nov 23, 2009 | Reply
yah for the first it is 3/7
for the second well there are 96 total possibilities and taht is all i really get. jsut write them all out!
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By cidyah on Nov 23, 2009 | Reply
3 marbles can be chosen out of 14 in 14C3 = 364 ways.
2 green out of 6 can be chosen in 6C2 = 15 ways
The other can be chosen from the remaining non-green 8 in 8C1 = 8 ways.
P(2 green, 1 other ) = (6C2)(8C1) / (14C3) = (15)(8) / 364 = 120/364 = 30/91 ways.
P(3 greens) = 6C3 / 14C3 = 20/364
P(3 reds) = 4C3 / 14C3 = 4 / 364
P(3 blues) = 4C3 / 14C3 = 4 / 364
P(all 3 of same color) = (20+4+4) / 364 = 28/364 = 1/13
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By Ben on Nov 23, 2009 | Reply
The probability of selecting two green marbles is the probability of getting a green marble the first time times the probability of getting one the second time. The total number of marbles is 6+4+4 = 14, and after taking one out there are 13 left. So, the probability is
(6/14) * (5/13) = 15/91
The probability all three are the same is the probability that you get all reds plus the probability of getting all blues plus the probability of getting all greens. So you have:
(6/14)(5/13)(4/12) + (4/14)(3/13)(2/12) + (4/14)(3/13)(2/12)
= (6p3 + 4p3 + 4p3)/(14p3) =
1/13
Cidya is right for the first part, I forgot about the third marble
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