Suppose that the time between emergency calls to a small suburban fire station follows an exponential distribution with an average rate of 1.8 calls per day Phil the fireman has just clocked on. The probability ofa call in the next 15 minutes is Phil has nearly finished his shift: 15 minutes to go. There has been no call during his shift so far. The probability of a call in the next 15 minutes is Judy works a 10-hour shift, Mondays to Thursdays. The probability that she has no calls in a shift is Judy works a 10-hour shift, Mondays to Thursdays. Assuming independence between days, the probability that Judy has no calls in four successive days is

1. L, V4- x²dx.

18. If the number of healthy fish f varies as the amount a of food available, how many fish would be present when 6 Ibs. of food are available? (Assume that 120 fish corresponds to 8 Ibs. of food.)

7.compute:2.7 H+4.15 -9 195/