Question

Easy probability question...
A container holds 13 red marbles, 9 blue marbles, and 16 green marbles. You will randomly select two marbles without replacement.
How many ways can you select the marbles?
What is the probability that you select 2 red marbles?
What is the probability that you select a green marble and then a red marble?

Answer 1

for the first one im guessing its 2/38

Answer 2

oh okay so what do i put for P?

Answer 3

Sorry, my bad.

Answer 4

lol so just forget about that equation?

Answer 5

TM total marbles = R + B +G
First draw P(R) = R/TM, P(B) = B/TM, P(G) = G/TM
Then second draw you have to consider condition probabilities such as
P(G|G) = (G - 1)/(TM-1)
PG|B) = G/(TM-1)
ect
then use Baye's formual

Answer 6

what does P stand for Probability?

Answer 7

P(G) means the probability of green
P(G|B) means the probability of green given previous draw bllue

Answer 8

oh okay but there are a total of 38 marbles and for the first question is ask, How many ways can you select the marbles? it should be 2/38 cause you take 2 marbles out

Answer 9

right?

Answer 10

MT! is they were all different color
For different colors
MT!/(R!B!G!)
It's divided by R! because it repeats that many times

Answer 11

so what does MT! equal?

Answer 12

why always marbles?

Answer 13

MT to marbles = #R + #B +#G= R+B+G

Answer 14

38! = 38X37X36 ... X1
very large and probably wont show up on calulator

Answer 15

if you care about the order then there are 38*37 ways to pick 2 marbles

Answer 16

Theres three colors

Answer 17

there are 13*12 ways to pick two reds

so the prob is (13*12)/(38*37)

Answer 18

oh okay thanks both for taking the time to help me :)

Answer 19

i got 151.89

Answer 20

for what?

Answer 21

(13*12)/(38*37)

Answer 22

you might want to try that again

Answer 23

Probabilities are always less than or equal to 1

Answer 24

You can't get an answer greater than 1; at least not in this scope.

Answer 25

parentheses are important

Answer 26

so i have to put it in fraction

Answer 27

\(\frac{13\times 12}{38\times37}\) is what you have to compute.

Answer 28

156/1406

Answer 29

that's is correct. (156/1406 = (13*12)/(38/37))

Answer 30

oh okay thanks for the help :)

Answer 31

umm who wants the medal?

Answer 32

oh i didn't work as much as the others.. :p thanks

Answer 33

lol welcome, and i became of fan of the others who helped

Answer 34

*a fan