Question

A jar contains 26 marbles. It has 10 red, 8 black, and 8 green marbles. Two marbles are drawn; the first is not returned before the second one is drawn. What is the probability that both marbles are green?

P(both green) = 8/13
P(both green) = 28/325
P(both green) = 32/325
P(both green) = 14/169

Answer 1

I think the answer is 14/169. 8/13 times 7/26 equals 14/169

Answer 2

How did you get there?

Answer 3

Like how did you 8/13 and 7/26?

Answer 4

There is 8 marbles out of 26 that are green. After picking out a marble from those 8 marbles, there are only 7 marbles that are green. Thats how I got there

Answer 5

Ok. I have a few more, would you mind helping me?

Answer 6

Yes

Answer 7

But I'm a bit slow since I'm helping 2 people including you.

Answer 8

By accident, six burned-out bulbs have been mixed in with 26 good ones. Ken is replacing old bulbs in his house. If he selects two bulbs at random from the box of 32, what is the probability they both work?

P(both work) = 325/512
P(both work) = 325/496
P(both work) = 169/256
P(both work) = 169/248

Answer 9

Okay that's fine!

Answer 10

I think its A

Answer 11

can you explain?

Answer 12

There are 26 bulbs out of 32 bulbs that work. If he takes out one, there is 25 left. So I multiplied 13/16 (simplified version of 26/32) and 25/32. Oh wait let me revise

Answer 13

OK

Answer 14

The answer is B. There are 26 bulbs out of 32 bulbs that work. If he takes out one, there are 25 left out of 31 bulbs. I multiplied 13/16 and 25/31

Answer 15

Ok great! thank you!

Answer 16

No problem. Can you fan+medal

Answer 17

Yes!