Posted by liz on .
3 red balls, 4 green balls, and 5 yellow balls are in a bag. If 2 balls are drawn randomly (without replacement) find the probability that the balls are different colors.
I got 47/66 that the balls are different colors...is that right?

Math for the middle school and elementary teacher 
MathMate,
Correct! Welldone!
P(RR)=(3/12)(2/11)=6/132
P(GG)=(4/12)(3/11)=12/132
P(YY)=(5/12)(4/11)=20/132
Probability to draw two of same colour
=(6+12+20)/132=19/66
=>
Probability to draw two of different colours
=(6619)/66=47/66 
Math for the middle school and elementary teacher 
bobpursley,
http://www.futureaccountant.com/probability/problemssolutions/drawingpickingselectingtwothreemoreballsboxbagurn04.php and many variations of the same bag.

Math for the middle school and elementary teacher 
liz,
Thank you very much for you help:)