Question

A jar has 6 blue balls and 4 yellow balls. If two are drawn without replacement, whats the probability that neither ball is yellow?

Answer 1

That means that both balls or blue.

\(\color{Black}{\Rightarrow \large {6 \over 10} \times {5 \over 9} }\)

Answer 2

why wouldn't you use something like combinations?

Answer 3

Why would you try to use combinations here? :)

Answer 4

I don't know! There are a lot of problems like these and in most of them you use combinations

Answer 5

Combinations are used in other kinds of problems. Not the simple probability :)

Answer 6

thanks for your help though :)

Answer 7

yw :D

Answer 8

alright I understand

Answer 9

The hypergeometric distribution applies (sampling without replacement)
\[P(2yellow)=\frac{\left(\begin{matrix}6 \\ 2\end{matrix}\right)\left(\begin{matrix}4 \\ 0\end{matrix}\right)}{\left(\begin{matrix}10 \\ 2\end{matrix}\right)}\]

Answer 10

So we have:
\[P(2yellow)=\frac{6\times 5\times 2}{2\times 10\times 9}\]