Answer:
Not purchase insurance
Explanation:
The probability of rain is 0.20
=> The probability of the not rain situation is: 1 - 0.2 = 0.8
If David does not buy the insurance, the expected net profit he would receive can be calculated as following:
Expected net profit = Probability of rain x Net profit when its rains + Probability of not rain x Net profit when it does not rain
= 0.20 x 40,000 + 0.8 x 100,000 = $88,000
If David buy the insurance:
+) When it does not rain: He will receive net profit of $100,000
+) When it rains: He will receive $40,000 as profit and $100,000 as insurance coverage
So that:
Expected net profit = Probability of rain x Net profit when its rains + Probability of not rain x Net profit when it does not rain - Insurance fee
= 0.2 x (40,000 + 100,000) + 0.8 x 100,000 - 25,000 = $83,000
As we can see, the expected net profit David receives when buying insurance is less than when he does not buy, so that he should not buy the insurance.