A man riding his bicycle covers 150 m in 25 seconds. What is his speed in Km/hr

21.6

Speed = \(\frac{ Distance}{ Time}\)

Speed =  \(\frac{150}{ 25}\) m/s

Speed in km/hr:

Speed = \(\frac{150}{ 25}\) x \(\frac{18}{5}\)

Speed =6 x \(\frac{18}{5}\)

Speed = \(\frac{108}{5}\)

Speed = 21.6 km/hr

*Note* 

In order to convert km/hr to m/s - multiply by  \(\frac{ 5}{ 18}\)

In order to convert m/s to kn/hr - multiply by  \(\frac{ 18}{ 5}\)