Question 1
2 marksSam has four coins: 10p, 20p, 50p and £1.
He picks two different coins.
List all the possible total amounts of money he could pick.
Model answer
Pair 10p with each larger coin: 10p + 20p = 30p, 10p + 50p = 60p, 10p + £1 = £1.10
Pair 20p with each larger coin: 20p + 50p = 70p, 20p + £1 = £1.20
Pair 50p with £1: 50p + £1 = £1.50
Totals: 30p, 60p, 70p, £1.10, £1.20, £1.50
Explanation
List systematically: pair the smallest coin with each of the others, then the next smallest with each larger coin, and so on. This makes sure you include every pair exactly once (10p + 20p is the same pair as 20p + 10p).
Mark scheme
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2 marks
B2 for all six totals: 30p, 60p, £1.10, 70p, £1.20, £1.50 (and no others)
any order; B1 for at least four correct totals with no more than one incorrect or repeated