Posted by makeeda on .
a sock drawer has 2 blue pair,4 white pair,4 black pair? what is the probability you will pick out a black pair ?
i think is 2/10 that how i get my answer but not for sure that correct

math 
Reiny,
depends if the socks are bundled in pairs or as singles.
If in pairs, ...
you have 10 pairs of which 4 are black, you want to pick one black pair.
prob = 4/10 or 2/5
if they are singles, ...
you have 8 black, 8 white, and 4 blue socks for a total of 20 socks.
you want 2 consecutive blacks
prob = 8/20 x 7/19 = 56/380 = 14/95