(i)[3]
Find the value of $x$.
(ii)[3]
If a randomly chosen member is an Advanced swimmer, find the probability that the member is male.
Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
Club members are split into either ‘Advanced swimmers’ or ‘Beginners’. The fraction of members who are male is $x$, and $0.7$ of the males are Beginners. Of the females, $0.55$ are Advanced swimmers. The tree diagram displays this information. For a member chosen at random, the probability of being an Advanced swimmer is equal to the probability of being a Beginner.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Relevant probabilities $(1-x)$ and $0.45$ (or $0.3$) identified.” …
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