Cambridge A Level Mathematics 9709 — 2011 May/June Paper 6 · Variant 2
9709/62/M/J/11 · 1 question · 50 marks · ≈56 min
The question paper and its mark scheme, free to read here and free to download. This is Cambridge’s own paper, exactly as it was sat.
Question paper4 pages
Mark scheme6 pages
Answers below. Sit the paper first if you are practising.
Questions as text
Q2 · In Scotland, in November, on average 80% of days are cloudy
2 In Scotland, in November, on average 80% of days are cloudy. Assume that the weather on any one day is independent of the weather on other days. (i) Use a normal approximation to find the probability of there being fewer than 25 cloudy days in Scotland in November (30 days). [4] (ii) Give a reason why the use of a normal approximation is justified. [1]
Mark scheme: x 0 1 2 3 4 5 6 M1 Values 0 – 6 seen could be in list Prob 0.2 0.24 0.08 0.08 0.16 0.16 0.08 A1 [2] All correct (iii) Mean = Σxp = 2.56 (64/25) B1 [1] (iv) P(4, 5, 6) = 0.4(10/25) or 0.16 + 0.16 + 0.08 B1 ft ft their P(4, 5, 6) providing p < 1 = P(draw) × 0.4 M1 Multiplying by their P(draw) providing p < 1 = 0.2 × 0.4 = 0.08 (2/25) A1ft [3] Correct answer (v) P(J wins on nth go) M1 Mult by any pn or pn – 1, p < 1 = (0.2)n – 1 × 0.4 oe A1ft [2] ft their probs
What was in this paper
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What you needed in this session
Cambridge’s own grade thresholds for 2011 May/June, Paper 6 · Variant 2. A higher threshold means an easier paper — the bar moves with how the cohort did.