Statistics

Because of a recent incident in which a number of people became ill after eating undercooked hamburger meat, intensive interest has centered around the cooking time for hamburger patties.  In the past, the cooking time at a local fast food firm has been found to be uniformly distributed between 4 and 5 minutes.

a) A TV reporter, Jane Greer, came to the restaurant and observed the cooking time of her meat patty.  What is the probability that her burger was cooked less than 4.2 minutes?


b) If in a separate visit by Jane with four other reporters, each ordered one hamburger, what is the probability that at least two of the patties will be cooked less than 4.2 minutes?