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kaitsmom
May 25, 2010, 12:45 PM
Ok, we know how to do this if Sasha pulled one sock out, but this one is really confusing us.

The question is...
Sasha has a bag of 3 red socks, 3 blue socks, and 2 white socks. She pulls a sock out of the bag without looking, puts it back, and pulls another sock out of the bag without looking. What is the probability that she will pull out a white sock both times?

the given choices are a. 188 b. 1/9 c. 1/16 d. 1/24

we added all of the socks... 3+3+2=8
and came up with 1/8

and then we tried 2/3 given 2 white sock and 3 colors. But neither are given solutions. How do you figure out a probability for one color given two tries?

She is in 5th grade, and I am in college and I can't for the life of me figure this one out!!

galactus
May 25, 2010, 12:52 PM
There are 8 socks with 2 whites.

The probability of pulling a white is 2/8=1/4

Put it back and the probability remains the same for the second pull... 1/4

So, (1/4)(1/4)=1/16

kaitsmom
May 25, 2010, 01:02 PM
I actually just worked it out! I was looking at a more advanced question that someone else had posted.
P(2/8) X P(2/8)
P(1/4) X P(1/4)
1/4 x 1/4 = 1/16

Got IT!! Thank you! We went on to the other three questions she had just like this one, and we were hoping that we were right in the formula that I came up with. And thanks to your confirmation, I now know she will turn this one in correctly.

Thanks again. We will definitely be bookmarking this site.