How fast
Two cyclists ride 600 m. One takes 75 s. The other takes 60 s. Who is faster?
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The idea
The cyclist who takes 60 s is faster. Both ride 600 m, so less time means more speed.
Covering a distance means travelling that far. Speed is the distance covered in one unit of time.
Speed = distance ÷ time.
A cycle covers 900 m in 180 s. Its speed is 900 ÷ 180 = 5 m/s. The unit m/s means metres in each second.
Step 1 of 4
- A bus and a cycle both cover 900 m.
- The bus takes 90 s.
- The cycle takes 180 s.
- Bus: 10 m/s. Cycle: 5 m/s.
Distance = speed × time. Time = distance ÷ speed.
A train goes at 60 km/h. The unit km/h means kilometres in each hour. How long does it take to cover 240 km? Time = distance ÷ speed = 240 ÷ 60 = 4 h.