Answer:
a. 3,900
Step-by-step explanation:
We find the probability of healthy persons & the weak out of the total population in the town.
Probability of healthy persons
P(h) = 600/1000
P(h) = 0.6
Probability of weak persons
P(w) = 400/1000
P(w) = 0.4
We find the pay off for both the healthy and the weak, then add up to get the expected value or the minimal annual premium
Expected Value = 0.6*$500 + 0.4*$9000
Expected Value = $300 + $9000
Expected Value = $3,900
So, the annual premium must be at least $3,900.