Thread: 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..

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 ways to pick the three kittens, all of which are equally likely. Of these, there are combinations which result in three striped. So the probability is ...

4/35?

Originally Posted by puzzledwithpolynomials

4/35?

Right!