A person crosses a 600 m long street in 5 minutes. What is his speed in km per hour ?
A
3.6 km/hr
B
7.2 km/hr
C
8.4 km/hr
D
10 km/hr
Correct Answer: 7.2 km/hr
Speed :$$\eqalign{ & = \left( {\frac{{600}}{{5 \times 60}}} \right){\text{ m/sec}} \cr & = {\text{ 2 m/sec}} \cr & = \left( {2 \times \frac{{18}}{5}} \right){\text{ km/hr}} \cr & = {\text{ 7}}{\text{.2 km/hr}} \cr} $$