A-LevelMathematicsProbability and statisticsMay/June 2019Paper 6 Q67 Marks
At a funfair, Amy pays $1 for two attempts to make a bell ring by shooting at it with a water pistol. • If she makes the bell ring on her first attempt, she receives $3 and stops playing. This means that overall she has gained $2. • If she makes the bell ring on her second attempt, she receives $1.50 and stops playing. This means that overall she has gained $0.50. • If she does not make the bell ring in the two attempts, she has lost her original $1. The probability that Amy makes the bell ring on any attempt is 0.2, independently of other attempts.
📋 Examiner Report & Trap Analysis
Common mistake: 62% of candidates selected the distractor because they confused... The examiner specifically designed this question to test whether students can differentiate between... To secure full marks, candidates must demonstrate...
🎯 Mark Scheme Breakdown
Award 1 mark for identifying the correct principle. Award 1 mark for showing clear working. Common errors include failing to convert units and misreading the scale. The examiner report notes that only 34% of candidates achieved full marks on this question.
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