Answer:

Explanation:
When attempting probability problems we want to figure out the chances of something happening. This turns into something like:

In this case we have 8 red marbles, 2 green marbles, and 5 blue marbles in a bag. That brings us to a total of 15 marble.
Since we want to first draw a red marble the chance of that happening would be:

Now we replace the marble as stated in the problem so we then draw the next marble, which is green.

All that's left is to multipy the values we got:

That's our answer.