Graphs 3
3 marks · EasyA bus follows this journey:
| Stage | Time (minutes) | Distance from depot (km) |
|---|---|---|
| Start | 0 | 0 |
| A | 20 | 16 |
| B | 40 | 32 |
Calculate the bus's speed between start and A.
Calculate the speed between A and B.
State whether the bus changed speed, and how you know.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) 48 km/h
(b) 48 km/h
(c) No, the bus did not change speed, because both speeds are the same.
Common mistakes: Not converting time to hours.; Using distances from the wrong intervals.
Show mark scheme and worked solution
Marking points
M1 (a) · 1 mark · Calculates speed for Start to A: (16 km)/(20/60 h) = 16 / (1/3) = 48 km/h.
A1 (b) · 1 mark · Calculates speed for A to B: (32-16 km)/(40-20 min) = 16 km/20 min = 48 km/h.
B1 (c) · 1 mark · States no change (or both speeds the same) with correct explanation.
Worked solution
(a) 16 km in 20 min = 16/(20/60) = 48 km/h.
(b) (32-16) km in (40-20) min = 16/(20/60) = 48 km/h.
(c) The speeds are both 48 km/h, so the bus did not change speed.