A bag contains 12 one-dollar-bills and 6 hundred-dollar-bills. If 5 bills are randomly selected from the bag, what is the probability that 3 are one-dollar bills and 2 are hundred-dollar bills?
The answer should be 7 / 12 . 1/3 chance if the $100 and a 1/4 chance of the $1 . Then to make the numbers same multiply 1/3 by 4 and 1/4 by 3. Then you'll get 4/12+3/12=7/12
