Number 5
2 marks · EasyA student's weight is measured as 55 kg to the nearest 5 kg. Write down the lower and upper bounds for the weight.
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Lower bound: 52.5 kg, Upper bound: 57.5 kg
Also accept: 52.5 kg, 57.5 kg; 52.5 to 57.5 kg
Common mistakes: 50 and 60 kg; 55 ± 5 kg
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Marking points
B1 · 1 mark · Correct lower bound: 52.5 kg
B2 · 1 mark · Correct upper bound: 57.5 kg
Worked solution
A measurement to the nearest 5 kg means the weight could be 2.5 kg above or below.
Lower bound = 55 - 2.5 = 52.5 kg. Upper bound = 55 + 2.5 = 57.5 kg.