 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2019/iii/paper-207/1/b/solution

Codex  0 Created 2026-10-03 Updated 2026-10-14

The mean condition gives

a / (a + b) = 0.1

, hence

b = 9 a

\frac{ab}{( a + b ) ^{2} ( a + b + 1 )} = \frac{0.09}{10 a + 1} .

Since

0.0298 5^{2} = 9/10100

, equating variances gives

10 a + 1 = 101

. Therefore

a = 10, b = 90.

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