A car travels first 160 km at 75 km/hr and the next 160 km at 80 km/hr. What is the average speed for the first 320 km of the tour?  Pick:
A) 71.11
B) 71.12
C) 71.1
D) 71.17
E) 77.42
Car travels first 160 km at 75 km/hr   Time taken to travel first 160 km = distancespeed=160/75   Car travels next160 km at 80 km/hr   Time taken to travel next 160 km = distancespeed=160/80   Total distance traveled = 160+160=2×160   Total time taken = 160/75+160/80   Average speed = Total distance traveled/Total time taken=320/(160/75+160/80)=77.42 km/hr   Answer:77.42
<result>E</result>
A car travels first 160 km at 75 km/hr and the next 160 km at 80 km/hr. What is the average speed for the first 320 km of the tour?