A person crosses a 720 m long street in 12 minutes. What is his speed in km per hour?  Pick one
A) 3.6 B) 4.5 C) 4.8 D) 5.4 E) 5.5

Rationale: "speed = 720 / ( 12 x 60 ) m / sec = 1 m / sec . converting m / sec to km / hr = 1 x ( 18 / 5 ) km / hr = 3.6 km / hr . answer : a"
Answer: A