1.A certain coaster has 3 cars ,and a passenger is equally likely to
ride in any 1 of the 3 cars each time that passenger rides the roller
coaster . I f a certain passenger is to ride the roller coaster 3
times ,what is the probability that the passenger will ride in each of
the 3 cars?
2.If n is the product of the integers from 1 to 20 inclusive,what is the greatest integer k for which 2的k次方 is a factor of n?
我看不懂这两道题,请问有没有高手可以帮助我。非常感谢 | 
