+556 The Boston weatherman says there is a 75 percent chance of rain every day of the Labor Day four-day weekend. If it doesn't rain, then the weather will be sunny. Paul and Yuri want it to be sunny one of those days for a World War III preenactment, but if it's sunny for more than one day they won't know what to do with themselves. What is the probability they get the weather they want? Give your answer as a fraction.
+355 There are 4 ways to choose which 3 days it rains. It would be
((3/4)^3)(1/4) = 27/256 because each day has a 3/4 chance of rain and 1/4 chance of sunshine.
For each of the 4 ways this can happen, that would be:
4 * (27/256)
27/64
