Question

A bag of marbles contains 8 red marbles and 5 green marbles. Three marbles are drawn at random at the same time. Find the probability that all three are red.

Answer 1

8 out of 13

Answer 2

\[{{8 \choose 3}\over {13 \choose 3}}\]

Answer 3

I assume you're familiar with choose notation.

Answer 4

Who me?

Answer 5

Well either you, or the original poster. Whomever wants to read/understand my answer.

Answer 6

it's not 8 out of 13 though. That'd be about 61 percent

Answer 7

Well yours is eight thirds over thirteen thirds right?

Answer 8

no. it's choose notation.

\[{n \choose k} = {n! \over k!(n-k)!}\]

Answer 9

Ok yepp then i have no clue lol

Answer 10

that's ok. it's a fun thing to learn about.

Answer 11

I'd rather stay away from the complicated stuff if you can do it the easy way i choose that.

Answer 12

Basically it boils down to :
How many different ways can we pick 3 red marbles from a set of 8 red marbles.

Then we divide that by the number of different ways we can choose 3 marbles from a bag of 13 marbles.

Answer 13

mhm.. I did that in like 4th grade so i really dont remember it lol

Answer 14

I'm not sure it's the same as what you're remembering.. But in any case there are 56 different ways you can pick 3 red marbles from a set of 8 red marbles.

Answer 15

And there are 286 ways you can pick any 3 marbles from a bag of 13 marbles.

Answer 16

ugh huh..

Answer 17

so 56/286 = .1958 or 19.6%

Answer 18

Is the probability you will grab exactly 3 red marbles.

Answer 19

I get it now, thank you.

Answer 20

This function is often built into calculators as the C function

Answer 21

Are you really smart brain wise or calculator wise or just incredibly smart period?

Answer 22

hrm.. tough one to answer. Probably I have just taken a lot of math classes. ;)

Answer 23

Oh mmk i see.