Posted by **kim** on Friday, July 27, 2012 at 1:43pm.

There are 6 pairs of black socks and 6 pairs of white socksWhat is the probability to pick a pair of black or white socks when 2 socks are selected randomly in darkness?M

- Math -
**Reo**, Friday, July 27, 2012 at 1:57pm
I think it's nCk which the total of socks would be 12 since we have 6 whites and 6 black. you would have to choose 2. in that case order does not matter and we use the combination formula 12C2 = 66 possible ways.

- Math -
**Reiny**, Friday, July 27, 2012 at 2:18pm
could be either BB or WW

Prob(BB) = (6/12)(5/11) = 5/22

which is the same as the prob(WW)

so prob of either WW or BB = 2(5/22) = 10/22

(note only other cases are WB and BW

and the prob of those = 2(6/12)(6/11) = 2/11 or 12/22

and prob of all cases = 10/22 + 12/22 = 22/22 = 1 )

All is good!

- typo - Math -
**Reiny**, Friday, July 27, 2012 at 2:21pm
correction in 3rd last line, should be

and the prob of those = 2(6/12)(6/11) = **6/11** or 12/22

## Answer this Question

## Related Questions

- maths - michael has 10 pairs of black socks,8 pairs of white socks&7 pairs of ...
- Math - Mario has large drawer with only white and blacks socks. He has 3 times ...
- MATHS - Could you please explain how to do this question? Thank you very much. ...
- math - a sock drawer contains 10 white socks, 6 black socks, and 8 blue socks. ...
- math - Paul has 8 white socks, 4 blue socks,10 grey socks, and 12 black socks in...
- math probability - A man is camping. He has packed 8 black socks, 8 blue socks, ...
- math - a draw holds 5 navy socks, 7 white socks and 6 black socks. if two socks ...
- math - Mariko walks into her dark room to pull socks out of the dresser. If she ...
- Math - I have 6 pairs of socks lying unmatched in my dresser drawer. Each pair ...
- math - A drawer contains 7 black socks, 5 white socks, and 3 brown socks. What ...