This Exam P sample reference tests Expected Value. The expected unreduced loss is 30(0.01)+10(0.05)=0.80. A target profit of 0.25 from a premium of 1 leaves 0.75 for expected reimbursement, so the reimbursement share is 0.75/0.80=0.9375, choice E.
These notes identify the calculation error associated with each wrong letter when that error is reproducible.
AThe value 0.20 is the expected profit if all of the 0.80 expected gross loss were reimbursed; it is a profit amount, not the reimbursement share.
BThe ratio 0.25/0.80=0.3125 divides target profit by expected loss, but q must fund the 0.75 reimbursement budget left after target profit.
CThe value 0.46875 results from halving the required reimbursement budget while using a gross-loss total that already includes both covered causes.
DThe value 0.80 is the expected gross loss per policyholder, expressed in premium units, rather than a proportion selected to meet the profit target.
Original practice · fully worked
Original variant: equipment protection cooperative
An equipment protection cooperative collects an annual fee of 100 dollars per member. A member is expected to incur 0.30 sensor failures costing 80 dollars each and 0.04 power-surge failures costing 400 dollars each during the year. The cooperative reimburses the same fraction of every covered loss and wants expected surplus of 75 dollars per member, with no other expenses. Calculate that reimbursement fraction.
A 0.250
B 0.375
C 0.400
D 0.625
E 0.750
Variant answer in brief
Expected covered loss is 0.30(80)+0.04(400)=40 dollars. The surplus target leaves 25 dollars for reimbursement, so the common fraction is 25/40=0.625, choice D.
Setup
Setup
Let q denote the common fraction of each loss paid by the cooperative.
fee=100,target surplus=75
Model
Model
Add frequency times severity across the two failure sources to obtain expected covered loss.
E[L]=0.30(80)+0.04(400)
Compute
Compute
Equate fee less expected reimbursement to the target surplus.
E[L]=24+16=40
100−40q=75
q=4025=0.625
Answer
Answer
The cooperative should reimburse 62.5% of every covered loss.
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