Originally Posted by

**argr78** 1) A parking lot contains 100 cars that all look quite nice from the outside. However K of these cars happen to be lemons. The number K is shown to lie in the range {0,1,...,9}, with all values equally likely.

a) We test-drive 20 distinct cars chosen at random and to our pleasant surprise, none of them turns out to be a lemon. Given this knowledge, what is the probability that K=0?

b) Repeat part (a) when the 20 cars are again chosen at random, but now with replacement; that is, at each test-drive each car is equally likely to be selected, irrespective of whether it was previously selected.