OpenStudy (anonymous):

What did I do wrong? (Probability) A bag of marbles has 12 red, 7 yellow, 5 blue and 1 white. Find the probability of selecting 4 marbles from the bag where all 4 are red. A. 1/64 B. 9/230 C. 1/4 D. 1/7590 ___ I got 1/12650 which isn't even an option. I did this my multiplying 1/25*2/25*3*25*4/25. Which is not an option. And then 12/390625 by multiplying 4/25*3/24*2/22*1/21 which is also not an option.

Vocaloid (vocaloid):

there are 12 red marbles, so if we assume there is no replacement it would be (12/25)*(11/25)*(10/25)*(9/25) if we assume replacement, it would simply be (12/25)^4

OpenStudy (anonymous):

Oh wow.. I put the 4 in place of 12 as the starting point.. Thanks @Vocaloid

Vocaloid (vocaloid):

ahh, small correction to my formula (12/25)*(11/24)*(10/23)*(9/22)

Vocaloid (vocaloid):

but yea, you're on the right track now :)

OpenStudy (anonymous):

Thanks :)

OpenStudy (anonymous):

It's B. Thanks!