 Solution

ID: past-exam-of-the-mathematics-course-of-the-year-1-of-the-natural-sciences-course-of-the-university-of-cambridge/2010/paper-2/17/a/i/solution

P (R) = \frac{1}{2} \frac{20}{50} + \frac{1}{2} \frac{180}{350} = \frac{1}{5} + \frac{9}{35} = \frac{16}{35} .

The large difference in jar sizes does not change their equal selection probabilities; pooling their contents would describe a different experiment.

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