Question

In a bag there are 2 black and 4 white identical rings. Two rings are drawn from the bag at random. Find the probability that only one of them is white.

Answer 1

first one is black AND second one is white OR first one is white AND second one is black
is one way to proceed

Answer 2

\[\frac{2}{6}\times \frac{4}{5}+\frac{4}{6}\times \frac{1}{5}\] is one way
there are others

Answer 3

for example you could compute
\[\frac{\binom{4}{1}\times \binom{2}{1}}{\binom{6}{2}}\]

Answer 4

second way is probably snappier, gives
\[\frac{8}{15}\] right away

Answer 5

@satellite73
May be there is a mistake in your second post? Can you please explain why does the second way give the right result?

Answer 6

thank you :)