Time = distance ÷ speed.
If the bus covers 40 km every hour, division tells us how many groups of 40 km fit into the full distance.
PRIMARY 7 · DISTANCE, SPEED AND TIME
The School Journey Planner
Use the relationship between distance, speed and time to make a journey plan that works.
THE SITUATION
The science visit begins at noon. Will the class arrive on time?
A school bus must travel 120 km. It moves at an average speed of 40 km/h and leaves school at 8:00 a.m.
WHAT ARE WE TRYING TO SOLVE?Find the travelling time, then add it to the departure time.
Kilometres ÷ kilometres per hour.
The kilometres cancel, leaving hours. Units help us check that we selected the correct operation.
120 km ÷ 40 km/h
Travelling time: 120 ÷ 40 = 3 hours
Departure: 8:00 a.m.
Arrival: 8:00 a.m. + 3 hours
The bus arrives at 11:00 a.m.—one hour early.
15-QUESTION PRACTICE
Plan the next journey.
Begin with five warm-ups, apply the rule in five journey situations, then finish with five reasoning challenges. Write the rule before touching the numbers.
1. A bus travels 150 km at 50 km/h. How long does the journey take?
2. If that bus leaves at 9:30 a.m., when will it arrive?
3. A minibus covers 240 km at 60 km/h. How long does it travel?
4. If the minibus leaves at 7:45 a.m., when does it arrive?
5. A car travels at 50 km/h for 3 hours. What distance does it cover?
GUIDED APPLICATION · 6–10
Choose the correct rule from distance, speed and time.
6. A bus covers 180 km in 3 hours. What is its average speed?
7. How long does a 90 km journey take at 45 km/h?
8. A vehicle travels at 40 km/h for 2½ hours. What distance does it cover?
9. A bus leaves at 8:00 a.m., travels 150 km at 50 km/h and stops for 30 minutes. When does it arrive?
10. For a 120 km journey, how much time is saved by travelling at 60 km/h instead of 40 km/h?
REASONING CHALLENGE · 11–15
Include stops, deadlines and more than one part of a journey.