Units & Time: Eduqas GCSE Higher June 2018 Paper 2 Q11

Higher June 2018 Paper 2 Q11

EduqasHigherCurrent spec8 marksUnits & Time Volume & Surface Area

11.

(a) Wayne says,
‘6·5 m² is the same as 650 cm², because there are 100 cm in 1 metre.’

Maria says,
‘6·5 m² is the same as 65 000 cm².’

Explain why Maria is correct. [1]

(b)

(i) The area of the water surface of Maria’s pond is 6·5 m².
She measures the depth of the pond in 5 different places using a measuring stick.
The 5 depths recorded by Maria are 120 cm, 120 cm, 130 cm, 140 cm and 140 cm.

Maria buys a liquid treatment for pond water.
The instructions state:

Use 0·5 litres of this treatment for every 1800 litres of pond water.

Calculate an approximate value for the quantity of the liquid treatment Maria needs to use in her pond.
You must give units at each stage of your working and give your answer in litres.
You must show all your working. [5]

(ii) Explain any decision you made in calculating an approximate value for the quantity of the liquid treatment needed.
What could be done to improve the accuracy of this value? [2]

Scheme	Marks	Comments
Explanation, e.g. ‘1m² = 10 000cm² ‘, ‘as this is area not length’, ‘1m² is 100cm by 100cm’	E1	Accept a diagram showing 1m by 1m is 100cm by 100cm

Mark scheme (b)

Scheme	Marks	Comments
(b)(i) \(6.5\times\) ‘a value between 1.2m and 1.4m inclusive’	M1	Place value may not be correct
\(65000\times120\) or \(6.5\times1.2\) to \(65000\times140\) or \(6.5\times1.4\)	M1	Place value must be consistent, although may include conversion to litres, \(\div1000\) or \(\times1000\) respectively \((65000\times130 = 8\,450\,000\) or \(6.5\times1.3 = 8.45)\) FT ‘their (120+120+130+140+140) ÷ 5’
Answer in the range 7 800 000cm³ to 9 100 000cm³, or 7.8m³ to 9.1m³, or 7800 litres to 9100 litres	A1	Accept embedded within further calculation Any units given must be correct FT correct evaluation using ‘their (120+120+130+140+140) ÷ 5’
(7800 litres to 9100 litres) \(\div1800\times0.5\), or (7800 litres to 9100 litres) \(\div3600\), or equivalent	m1	Place value may not be correct FT ‘their volume’ provided at least M1 previously awarded Accept rounded or truncated from correct working
Answer in the range 2.16 (litres) to 2.53 (litres)	A1	CAO
(b)(ii) Explanation of decision, e.g. ‘I only used one of the depths’, ‘I used an average depth but this may not be accurate’, ‘I used an average depth but there were only 5 readings’, ‘I used the median depth of just a few readings’ AND Improvement of method, e.g. ‘take more depth readings’, ‘I could have used the average depth’, ‘I could have looked at the shallowest and deepest readings’, ‘get more information’, ‘consider the shape of the pond’	E2	This explanation must follow from the method they used. E1 for either the decision or the improvement of the method Allow ‘I used one of the depths’, ‘I used the median’, ‘I used an average depth’, ‘I used the mean depth’
	(8)