Suppose there are 1000 off shore drilling rigs operating in the Gulf of Mexico. Each has been designed so that the odds of it ever blowing up or failing and causing a major spill in any given year after installation is 1 chance in 50,000.

(1) If no more are erected, what is the probability that we would see at least one of them failing during the next 20 years?

(2) What is the probabilty that none of them fail during the next 10 years?