Answer:
4/91
Explanation:
There are a total of 15 marbles. In the first selection there are 15 marbles and 6 are blue. That would be 6/15.
Since we are not replacing marbles, we now have 14 marbles and we want to select one of the 5 white marbles. That would be 5/14.
Lastly we now only have 13 marbles and of those we want to select one of the 4 red ones. That would be 4/13.
Now we take these 3 fractions and multiply them together.
6/15(5/14)(4/13). I am going to try to make this a little easier and see if I can find any factors that any top number shares with any bottom number.
I see 5 on the top shares a common factor with 15 on the bottom. I will divide these numbers by 3, so now I have
6/3(1/14)(4/14). I think that I can do better than that. I see that 6 on the top and 3 on the bottom share a common factor of 3. I will divide both of these numbers by 3. Which will give me:
2/1(1/14)(4/13) I see a 4 on top and a 14 on the bottom. Those are both divisible by 2 so, I will divided them both by 2 and that leaves me with
2/1(1/7)(2/13) That is a lot easier, now I will just multiple the top numbers and multiply the bottom numbers to get
4/91