Higher November 2017 Paper 6 Q13

OCRHigherCurrent spec5 marksSimilar Shapes

13 A model railway is built using the scale 1 : 87.

(a) On the model railway, the distance between the rails is 16.5 mm.

Section of railway track with two rails across sleepers; the gap between the rails is labelled distance between the rails

Calculate, in metres, the distance between the rails for a full-size train.

........................................ metres [2]

(b) The volume of a full-size train carriage is 220 m³.
Trevor calculates the volume of a model train carriage to be 334 cm³ correct to 3 significant figures.

Is Trevor’s calculation correct?
Show how you decide. [3]

Answer	Marks	Part marks and guidance
1.4355 or 1.436 or 1.44	2	M1 for 16.5 × 87 possibly soi by figs 14355, 1436 or 144

Mark scheme (b)

Answer	Marks	Part marks and guidance
Yes (Trevor is correct) because Eg \(220 \div 87^3 \times 100^3 = 334.[\ldots]\) or \(334 \times 87^3 \div 100^3 = 219.9\ldots\) to 220	3	M2 for \(220 \div 87^3 \times 100^3\) or \(334 \times 87^3 \div 100^3\) OR B1 for \(87^3\) or 658503 or \(100^3\) or 1000000 soi