A person crosses an 800m long street in 5 minutes. What is his speed in km per hour?

Question: A person crosses an 800m long street in 5 minutes. What is his speed in km per hour?

Solution:
distance = 800m = 0.8km
time = 5 minutes = 5/60 = 1/12 hour

speed = distance/time
= 0.8/(1/12) km per hour
= 9.6 km per hour.