Hi everyone, I'd like some help please
1) A basket contains 7 red apples and 4 yellow apples. A sample of 3 apples is drawn. Find the probabilities that the sample contains more red than yellow apples.
So, I figure I have to find the sum of the probabilities that the sample has:
-4 red apples and 3 yellow apples, 5 red apples and 2 yellow apples, 6 red apples and 1 yellow apple, and 7 and 0 right....right?
I want to use combinations, right? Because I know that when it asked for all red apples I did (4 3) divided by (11 3)
*pretend that those numbers are on top of each other like in combination form*
and my second question...
2) given a certain number of balls, of which some are blue, pick 5 at random. thie probability that all 5 are blue is 1/2. determine the original number of balls and decide how many were blue
This one, I have no clue.
I've been looking and trying to understand what you've written for the last hour...and i'm still not understanding. are you sure that that answer is correct? that would give me 119/165, or 72%. i thought i would add the (7 2) and (4 1), not multiply them!