If 5 cards are drawn from a deck of 52 cards. Find the probability of obtaining
a) 4 cards of a single suit and 1 card of a different suit.
I think the answer is 13C4 * 48C1 divided by 52C5 ?
No, that's not correct.
We choose the suit 4C1 ways.
For each of those ways, we can pick the 5 cards 13C4 ways.
For each of those ways, there are 39 cards of other suits
(not 48), so we can choose it 39C1 ways.
Answer 
13 because there are 13 cards in one suit and you need 4 of them.
48 because there are 48 cards left from the 4 of a single suit you have.
That's one of your errors. You must subtract all 13 cards of the
suit you chose for the four from 52, which leaves 39. Subtracting only
4 leaves cards of the same suit. Your other error was leaving out the
4C1 for the ways to choose the suit for the four of the same suit.
divided by 52 because that is the total number of cards you have and you want 5
That part is correct.
I am really not sure because my teacher does not explain things. Lectures us on
it once and then he moves on.
Teachers are givern a syllabus of material to cover and they must cover it all
in the time they are allotted, or else their supervisors will ask them why they
did not cover all the material, and they will be in trouble. You should go see
your teacher outside of class and get him to give you additional help. He will
be glad to, I'm sure.
Edwin
