A fast bowler has a run-up of 125 m. If the speed at which he runs is 45 km/h, then how much time does he take to complete the run-up?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 10 seconds
Time = distance ÷ speed, with both in the same units. The distance is in metres and the speed in km/h, so the speed is first changed to m/s: 1 km/h = 1000 m in 3600 s = \(\frac{5}{18}\) m/s.
Speed in m/s: \(\displaystyle 45\times\frac{5}{18}=12.5\) m/s
Time to cover the 125 m run-up: \(\displaystyle\frac{125}{12.5}=10\) seconds