A person crosses a 1080 m long street in 10 minutes. What is his speed in km per hour?  Choose the correct choice from the following answers:
A) 4.1	B) 6.4	C) 4.8	D) 5.4	E) 5.5

Rationale: "speed = 1080 / ( 10 x 60 ) m / sec = 1.8 m / sec . converting m / sec to km / hr = 1.8 x ( 18 / 5 ) km / hr = 6.4 km / hr . answer : b"
Answer: B