math
posted by kaylee .
drawing a red checker from bag of 9 black checksrs and 6 red checkers, replacing it and drawing another red checker

The probability of drawing a red checker = # of red checkers/total. Since the red checker is replaced, the probability of drawing red the second time is the same.
The probability of both/all events occurring is found by multiplying the probabilities of the individual events.
I hope this helps. 
Billy takes two marbles, without replacement, from a bag that contains only six yellow marbles and three blue marbles.
What is the probability that he gets one marble of each color?