Question 7042
P(at least 1 red) is a lot of work. However, thankfully, we can think of it as 1 - P(3 black), which is a lot easier to compute.


P(BBB) = (4/9)*(3/8)*(2/7) = 1/21


so P(at least 1 red) = 1 - 1/21
P(at least 1 red) = 20/21


jon.