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?	Choose the correct choice from the following answers:	A) 71.11	B) 71.12	C) 71.1	D) 71.17	E) 77.42

Rationale: car travels first 160 km at 75 km / hr time taken to travel first 160 km = distancespeed = 160 / 75 car travels next 160 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 : e
Answer: E