MATH 12 HELP!
posted by the man on .
One bag contains 4 white balls and 6 black balls. Another bag contains 8 white balls and 2 black balls. A coin tossed to select a bad, then a ball is randomly selected from that bag.
Suppose white ball was drawn. What is the probability that it came from the first bag?

Since a coin toss is used to select either bag1 or bag2
the prob that bag1 is choses is 1/2
prob that a white ball is choses from bag1 = 4/10 = 2/5
so prob of your 'event' = (1/2)(2/5) = 1/5 
but the answer in my book says 1/3... Maybe its wrong?

PR=BROWN