From the mortality table extract below, calculate (i) the rate of mortality at age 30, and (ii) the natural (risk) premium for a one-year policy of sum assured Rs 1,000 on a life aged 30. Ignore interest and expenses.
| Age (x) | Number living (lₓ) | Number dying (dₓ) |
|---|---|---|
| 30 | 1,00,000 | 200 |
| 31 | 99,800 | 220 |
Step 1 — Rate of mortality at age 30.
The rate of mortality qₓ = dₓ ÷ lₓ.
Here d₃₀ = 200 and l₃₀ = 1,00,000, so
q₃₀ = 200 ÷ 1,00,000 = 0.002, i.e. 2 deaths per thousand lives.
Step 2 — Natural (risk) premium for one year.
Ignoring interest and expenses, the pure premium each life must pay for one year's cover equals the rate of mortality × sum assured, because the total so collected exactly meets the expected claims of those who die during the year.
Natural premium = q₃₀ × sum assured = 0.002 × Rs 1,000 = Rs 2.00.
Check (dual-solve). If all 1,00,000 lives each pay Rs 2, the fund collected = 1,00,000 × Rs 2 = Rs 2,00,000. The claims to be paid = 200 deaths × Rs 1,000 = Rs 2,00,000. The fund exactly equals the claims, confirming the premium of Rs 2.00 is correct.
(i) Rate of mortality at age 30 = 200 ÷ 1,00,000 = 0.002. (ii) Natural premium = 0.002 × Rs 1,000 = Rs 2.00 per year.
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