Math Is Fun Forum

karney

Guest

SweetTarts

In a certain package of SweetTarts there are 3 reds, 4 blues, 5 yellows, and 8 pinks.  What is the probability of simultaneously pulling 2 blue SweetTarts from the package?

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: SweetTarts

There are 20 tarts in all, so the probability of picking the first blue is 4/20 = 1/5.
If that happens, then afterwards there are 19 tarts left, 3 of which are blue.
Therefore, the probability of picking the second blue is 3/19.

Multiplying them together gives the overall probability as 3/95.

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Why did the vector cross the road?
It wanted to be normal.

karney

Guest

Re: SweetTarts

Mathysperson, thanks for the SweetTart answer.  What about pulling 2 blues simultaneously?

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: SweetTarts

That's the answer for pulling them simultaneously. I thought of it as pulling one out and then another, for ease of explanation, but as long as the first tart isn't put back in the bag before the second is chosen, the answer is unaffected.

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Why did the vector cross the road?
It wanted to be normal.

karney

Guest

Re: SweetTarts

Thanks for the explanation.  I really appreciate your help.

anbul

Member

Registered: 2009-06-08

Posts: 2

Re: SweetTarts

My question is a little similar. However simultaneously in the sweet tarts question, would be picking out 2 or more together? please explain further. Thanks

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: SweetTarts

Hi anbul;

  Mathsyperson is saying that as long as you don't replace any of the tarts you pick, picking them one at a time or two of them at once is the same.

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
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