1. ## Probabilty issues..

Of 7 kittens in a litter, 4 have stripes. Three kittens are picked at random. Find the odds of each event.
1) All three have stripes.
2) Only 1 has stripes.
3) One is not striped.
I am just...utterly stuck. I tried doing 4 CR 3/7 CR 4 for the first one, but that's apparently not correct..

2. Originally Posted by puzzledwithpolynomials
Of 7 kittens in a litter, 4 have stripes. Three kittens are picked at random. Find the odds of each event.
1) All three have stripes.
2) Only 1 has stripes.
3) One is not striped.
I am just...utterly stuck. I tried doing 4 CR 3/7 CR 4 for the first one, but that's apparently not correct..
puzzled,

You are very close.

There are $\binom{7}{3}$ ways to pick the three kittens, all of which are equally likely. Of these, there are $\binom{4}{3}$ combinations which result in three striped. So the probability is ...

3. 4/35?

4. Originally Posted by puzzledwithpolynomials
4/35?
Right!