Higher November 2018 Paper 3 Q18
18 A high speed train travels a distance of 487 km in 3 hours.
The distance is measured correct to the nearest kilometre.
The time is measured correct to the nearest minute.
By considering bounds, work out the average speed, in km/minute, of the train to a suitable degree of accuracy.
You must show all your working and give a reason for your answer. (5)
| Answer | Mark | Mark scheme |
|---|---|---|
| 2.7 with statement | B1 | for 179.5 or 180.5 or 180.4999... |
| B1 | for 486.5 or 487.5 or 487.4999... | |
| P1 | for a correct process to find a bound for average speed, eg [upper bound of distance] ÷ [lower bound of time] where \(487 \lt\) [UB of distance] \(\leqslant 487.5\) and \(179.5 \leqslant\) [LB of time] \(\lt 180\) or for [lower bound of distance] ÷ [upper bound of time] where \(486.5 \leqslant\) [LB of distance] \(\lt 487\) and \(180 \lt\) [UB of time] \(\leqslant 180.5\) | |
| A1 | (dep on all previous marks) for 2.695(2…) and 2.715(8…) with both values clearly coming from working with correct values | |
| C1 | for 2.7 from 2.695… and 2.715… and statement that both LB and UB round to 2.7 |
Additional guidance
Accept bounds truncated or rounded to at least 4 sig fig