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There are 8 TV sets, 6 are color and 2 are black-white. If 2

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joemama142000
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There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   21 Mar 2006, 17:04
There are 8 TV sets, 6 are color and 2 are black-white. If 2 sets are selected at random, what is the probability that at least one of them is color set?



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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   21 Mar 2006, 17:12
joemama142000 wrote:
There are 8 TV sets, 6 are color and 2 are black-white. If 2 sets are selected at random, what is the probability that at least one of them is color set?


1 - (2c2 / 8c2)

= 27/28
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   21 Mar 2006, 17:13
joemama142000 wrote:
There are 8 TV sets, 6 are color and 2 are black-white. If 2 sets are selected at random, what is the probability that at least one of them is color set?


What is the prob. that no colour sets are chosen in 2 attempts?
2/8 *1/7= a (too lazy to do the math)


therefore, the prob. to chose at least 2 color sets is 1-a
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   24 Mar 2006, 05:03
conocieur wrote:
joemama142000 wrote:
There are 8 TV sets, 6 are color and 2 are black-white. If 2 sets are selected at random, what is the probability that at least one of them is color set?


1 - (2c2 / 8c2)

= 27/28


i'm going a lil crazy, but what is 2c2 again?? ..

i had a totally different solution
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   24 Mar 2006, 05:21
Angela780 wrote:
conocieur wrote:
joemama142000 wrote:
There are 8 TV sets, 6 are color and 2 are black-white. If 2 sets are selected at random, what is the probability that at least one of them is color set?


1 - (2c2 / 8c2)

= 27/28


i'm going a lil crazy, but what is 2c2 again?? ..

i had a totally different solution


2c2 is number of ways to select 2 black/white tv sets out of 2....
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   24 Mar 2006, 05:53
SimaQ wrote:
Angela780 wrote:
conocieur wrote:
joemama142000 wrote:
There are 8 TV sets, 6 are color and 2 are black-white. If 2 sets are selected at random, what is the probability that at least one of them is color set?


1 - (2c2 / 8c2)

= 27/28


i'm going a lil crazy, but what is 2c2 again?? ..

i had a totally different solution


2c2 is number of ways to select 2 black/white tv sets out of 2....


ok Sima, please bear with me.. can you break the solution down step by step?
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SimaQ
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   24 Mar 2006, 06:07
OK....

First of all, to get the probability that at least one of the TV sets will be color we can use the following formula....

1-(the probability of choosing balck/white tv set both times)

To get that probability we have to calculate total favourable outcomes of choosing 2 black/white tv sets... which is 2c2 since we are calculating the number of ways to choose 2 tv sets out of 2....

... and divide it by the total number of possible outcomes... which is 8c2... since we have to choose 2 tv sets out of 8...

There may be other approaches, what approach did you use?
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   24 Mar 2006, 08:47
P(at least 1 is color) = 1 - P(both are black-white) = 1 - (2/8)(1/7) = 27/78
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink] New post   24 Mar 2006, 12:07
SimaQ wrote:
OK....

First of all, to get the probability that at least one of the TV sets will be color we can use the following formula....

1-(the probability of choosing balck/white tv set both times)

To get that probability we have to calculate total favourable outcomes of choosing 2 black/white tv sets... which is 2c2 since we are calculating the number of ways to choose 2 tv sets out of 2....

... and divide it by the total number of possible outcomes... which is 8c2... since we have to choose 2 tv sets out of 8...

There may be other approaches, what approach did you use?


my approach was this:

6 color tv..prob that 1 will be color 6/8, 2 black and white 2/7
6/8*2/7



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Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
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Thank you for understanding, and happy exploring!
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Re: There are 8 TV sets, 6 are color and 2 are black-white. If 2 [#permalink]
24 Mar 2006, 12:07
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