A pump manufacturer knows from past records that, in general, the probability of a certain specialty pump working continuously for fewer than 2 years is 0.3; the probability that it will work continuously for 2 to 5 years is 0.5, and the probability that it will work for more than 5 years is 0.2. An order of 8 such pumps has just been sent out to a customer: ?nd the probability that two will work for fewer than 2 years, ?ve will work for 2 to 5 years, and one will work for more than 5 years.