A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. Find the average speed for first 320 km of tour. Pick one:
A) 70.11 km/hr	B) 71.11 km/hr	C) 72.11 km/hr	D) 73.11 km/hr	E) None of these
Explanation:   We know Time = Distance/speed   So total time taken =   (160/64+160/80)=9/2hours   Time taken for 320 Km = 320∗2/9=71.11km/hr   Option 71.11 km/hr
<result>B</result>
A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. Find the average speed for first 320 km of tour.