A small town gets its water supply from three nearby lakes, A,B, and C. Sometimes in the late summer

the water level in a lake falls below a certain critical level.When this occurs, there is a risk that the water

from that lake will become polluted with E-Coli. If the watersupply to the town becomes polluted, the

residents are advised to boil their water. If only the waterlevel at lake A falls below the critical level,

experience has shown that the residents will have a 5% chance ofa boil water advisory. Similarly, if

only the water levels at lakes B or C fall below the criticallevel, chances of a boil water advisory are

4% and 7%, respectively. If two or more lakes fall below thecritical levels simultaneously, the risk

of a boil water advisory rises to 40%. Lake A falls below thecritical level in 30% of the summers,

while this number is 50% and 20% for lakes B and C,respectively. The probability that exactly two

lakes will fall below their critical levels simultaneously is12%, and it is equally likely to be any two of

the three. Finally, there is a 3% chance that all three lakeswill simultaneously fall below their critical

levels. During some summer in the future:

a) What is the probability that the residents will have a boilwater advisory? (answer:0.0914)

b) If the residents have a boil water advisory, what is theprobability that the water level will fall

below the critical level at lake B alone? (answer:0.1707)

c) If the residents have a boil water advisory, what is theprobability that the water level will fall

below the critical levels at two or more lakes simultaneously?(answer:0.6565)