A-LevelMathematicsProbability and statistics9709/52 · Feb/Mar 2020 · Q46 Marks
Richard has 3 blue candles, 2 red candles and 6 green candles. The candles are identical apart from their colours. He arranges the 11 candles in a line.
- (a)Find the number of different arrangements of the 11 candles if there is a red candle at each end.[2]
- (b)Find the number of different arrangements of the 11 candles if all the blue candles are together and the red candles are not together.[4]
Mark scheme
Marking points from the official mark scheme (Feb/Mar 2020). The mark or mark type is shown in brackets.
- M1 9! Alone on numerator, 3! x k or 6! × k on denominator
- A1
- M1 7! / k or 7k seen, k an integer > 0
- M1 m×n(n-1) or m× nC2 or m× nP2, n=7, 8 or 9, m an integer > 0
- M1 n = 8 used in above expression
- A1
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