# Math Help - Combination

1. ## Combination

There are 20 footballer and 15 basketballer attending a sport conference . THe number of women footballer and that of women basketballer are 12 and 5 respectively . Four participants from this group are selected randomly to chair some sessions of panel discussion .

(1) Find the probability that three footballer are selected .

I don really understand the question , these 3 footballer are selected from the 20 footballer 15 basketballer OR 12 footballer 5 basketballer ?

(2) Given that two women are selected , find the probability that both of them are footballer .

2. Originally Posted by thereddevils
There are 20 footballer and 15 basketballer attending a sport conference . THe number of women footballer and that of women basketballer are 12 and 5 respectively . Four participants from this group are selected randomly to chair some sessions of panel discussion .

(1) Find the probability that three footballer are selected .

I don really understand the question , these 3 footballer are selected from the 20 footballer 15 basketballer OR 12 footballer 5 basketballer ?

(2) Given that two women are selected , find the probability that both of them are doctors .
(1) $\frac{{20 \choose 3} \cdot {15 \choose 1}}{{35 \choose 4}}$. Your job is to understand where this answer has come from.

(2) I don't see anything in the question about doctors so this part is currently impossible to answer.

3. Originally Posted by mr fantastic
(1) $\frac{{20 \choose 3} \cdot {15 \choose 1}}{{35 \choose 4}}$. Your job is to understand where this answer has come from.

(2) I don't see anything in the question about doctors so this part is currently impossible to answer.
Sorry , not doctor but footballers .

4. Originally Posted by thereddevils
Sorry , not doctor but footballers .
$\frac{{12 \choose 2} \cdot {23 \choose 2}}{{17 \choose 2} \cdot {18 \choose 2}}$

5. Originally Posted by mr fantastic
$\frac{{12 \choose 2} \cdot {23 \choose 2}}{{17 \choose 2} \cdot {18 \choose 2}}$
but the answer given is 0.4853