Question

A bag contains 5 red marbles, 3 green marbles, and 2 blue marbles. If Nathan draws two marbles without replacing them, what is the probability he will draw 2 red marbles?

Answer 1

It would be a 2/9 chance.

Explanation:

So to start, the total amount of marbles is 10, as there's 5 red marbles, 3 green marbles, and 2 blue marbles.

With this, in the first draw, there's a 5/10 chance that a red one will be picked since there's 5 reds of the 10 total.

Since the marbles aren't put back, if a red's chosen in the first draw, it wouldn't be there in the second draw. Therefore in the second draw, there would be 4 reds and 9 in total.

With this, in the second draw, there's a 4/9 chance that a red one will be picked since there's 4 reds of the 9 total.

Now, combine these two probablities by multipliying them and you've got your answer!

5/10 * 4/9 = 20/90 ---> 2/9