An athlete runs 200 metres race in 24 seconds. What is his speed?
20 km/hr
25 km/hr
27.5 km/hr
30 km/hr
Explanation:
Speed = $\dfrac{Distance}{Time} = \dfrac{200}{24}m/s = \dfrac{200}{24}\times \dfrac{18}{5}$km/hr
= $\dfrac{40 \times 3}{4}km/hr = 10 \times 3$km/hr = 30km/hr