A man on tour travels first 160 km at 64 km/he and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is?	Choose the correct option:  A) 71.61 km/hr  B) 71.11 km/hr  C) 71.18 km/hr  D) 77.11 km/hr  E) 21.11 km/hr
Total time taken = (160/64 + 160/8) = 9/2 hrs.   Average speed = 320 * 2/9   =71.11 km/hr.   Answer:71.11 km/hr
<result>B</result>
A man on tour travels first 160 km at 64 km/he and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is?