An experiment is designed to test the potency of a drug on 20 rats. Previous animal studies have shown that a 10-mg dose is lethal 5% of the time within the first 4 hours; of the animals alive at 4...

An experiment is designed to test the potency of a drug on 20 rats. Previous animal studies have shown that a 10-mg dose is lethal 5% of the time within the first 4 hours; of the animals alive at 4 hours, 10% will die in the next 4 hours. (This is a 3 part problem)

a) What is the probability that 3 or more rats will die in the first 4 hours?

b) What is the probability that 0 rats will die in the 8 hour period?

c) What is the probability that 2 rats will die in the 8 hour period?