Exam questions · Maths · Ratio and Proportion
Units, Conversions and Scale
- 6 exam questions
- 19 marks
- 9 quick checks
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1 Convert [2 marks]
(a) Convert 0.45 km to metres. [1 mark] (b) Convert 5.2 kg to grams. [1 mark]
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Model answer
(a) \(0.45 \times 1000 = 450\) m. (b) \(5.2 \times 1000 = 5200\) g.
Mark scheme
- (a) 450 m — B1
- (b) 5200 g — B1
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2 Calculate [2 marks]
A bag of rice has a mass of 1.5 kg. Calculate how many 60 g portions can be made from the bag.
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Model answer
\(1.5\text{ kg} = 1500\) g, and \(1500 \div 60 = 25\) portions.
Mark scheme
- 1500 g seen, or \(1500 \div 60\) — M1
- 25 — A1
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3 Calculate [5 marks]
The diagram shows a scale drawing of a living room. The scale is 1 cm represents 2 m. (a) Calculate the real length of the room. [1 mark] (b) Calculate the real width of the room. [1 mark] A rug has an area of 21 m\(^2\). (c) What percentage of the floor of the room is covered by the rug? [3 marks]
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Model answer
(a) \(6 \times 2 = 12\) m. (b) \(3.5 \times 2 = 7\) m. (c) The floor area is \(12 \times 7 = 84\) m\(^2\), so the rug covers \(\dfrac{21}{84} = \dfrac{1}{4} = 25\%\).
Mark scheme
- (a) 12 m — B1
- (b) 7 m — B1
- (c) \(12 \times 7 = 84\) — M1
- (c) \(\dfrac{21}{84}\) or \(21 \div 84\) — M1
- (c) 25% — A1
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4 Calculate [3 marks]
A plan of a field has a scale of \(1 : 5000\). The field is 4.5 cm long on the plan. Calculate the real length of the field in metres.
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Model answer
\(4.5 \times 5000 = 22\,500\) cm, which is 225 m.
Mark scheme
- \(4.5 \times 5000\) — M1
- \(22\,500\) cm — M1
- 225 m — A1
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5 Calculate [3 marks]
A water tank has a volume of 2.4 m\(^3\). 1 m\(^3\) is 1000 litres. Calculate the volume of the tank in litres, and the number of 20-litre buckets needed to fill it.
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Model answer
\(2.4 \times 1000 = 2400\) litres. The number of buckets is \(2400 \div 20 = 120\).
Mark scheme
- \(2.4 \times 1000\) — M1
- 2400 litres — A1
- 120 buckets — B1
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6 Convert [4 marks]
(a) Convert 5 m\(^2\) to cm\(^2\). [2 marks] (b) Convert \(15\,000\) mm\(^2\) to cm\(^2\). [2 marks]
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Model answer
(a) \(1\text{ m}^2 = 10\,000\) cm\(^2\), so \(5 \times 10\,000 = 50\,000\) cm\(^2\). (b) \(1\text{ cm}^2 = 100\) mm\(^2\), so \(15\,000 \div 100 = 150\) cm\(^2\).
Mark scheme
- (a) \(5 \times 10\,000\) — M1
- (a) \(50\,000\) — A1
- (b) \(15\,000 \div 100\) — M1
- (b) 150 — A1
Quick check
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1
Change 3.6 km to metres.
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A: 3600 m
Multiply by 1000: \(3.6 \times 1000 = 3600\).
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2
Change 2450 g to kilograms.
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D: 2.45 kg
Divide by 1000: \(2450 \div 1000 = 2.45\).
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3
Change 0.75 litres to millilitres.
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C: 750 ml
Multiply by 1000: \(0.75 \times 1000 = 750\).
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4
Change 250 cm to metres.
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B: 2.5 m
Divide by 100: \(250 \div 100 = 2.5\).
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5
A map has a scale of \(1 : 50\,000\). Two towns are 4 cm apart on the map. What is the real distance?
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A: 2 km
\(4 \times 50\,000 = 200\,000\) cm. Divide by 100 to get 2000 m, then by 1000 to get 2 km.
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6
A scale drawing uses 1 cm to represent 2 m. A line on the drawing is 7 cm. How long is it in real life?
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D: 14 m
Multiply by the scale: \(7 \times 2 = 14\) m.
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7
A cake uses 250 g of flour. How many cakes can be made from a 2 kg bag?
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C: 8
\(2\text{ kg} = 2000\) g, and \(2000 \div 250 = 8\).
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8
How many cm\(^2\) are in 1 m\(^2\)?
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B: 10 000
A square metre is a square of side 100 cm, so its area is \(100 \times 100 = 10\,000\) cm\(^2\).
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9
Change 5 m\(^3\) to cm\(^3\).
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A: 5 000 000 cm\(^3\)
\(1\text{ m}^3 = 100^3 = 1\,000\,000\) cm\(^3\), so \(5\text{ m}^3 = 5\,000\,000\) cm\(^3\).