A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is:	Options
A) 35.55 km/hr B) 36 km/hr C) 71 km/hr D) 71.11 km/hr E) 70 km/hr
Total time taken =((160/64)+(160/80))hrs=9/2hrs.   Average speed =(320 x2/9)km/hr= 71.11 km/hr.   ANSWER 71.11 km/hr
<result>D</result>
A man on tour travels first 160 km at 64 km/hr and the next 160 km at 80 km/hr. The average speed for the first 320 km of the tour is: