A box contains 4 white balls and 5 red balls. I draw 3 of them out of the box, one at a time, and set them aside. What is the probability that the balls I draw alternate between the two colors?
You can case work.
Case 1: WRW=4/9*5/8*3/7=15/126
Case 2: RWR=5/9*4/8*4/7=10/63
Total is 25/126.
Your final total should be: 35/126 =5/18