Honors Problems #6

due Thursday, October 20, 2005

 

A drawer has 6 green socks and 2 red socks.  Two socks are drawn randomly without replacement.  What is the probability that they are a matching color?

 

A student has two bags of marbles:  Bag A contains 8 red and 3 black marbles, and Bag B contains 5 red and 7 black marbles.  She randomly selects a bag then draws one marble at random.  It is black.  What is the probability that it came from bag B?