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:
a) 35.55 km/hr
b) 36 km/hr
c) 71.11 km/hr
d) 71 km/hr
e) 69.69km/hr
a) 35.55 km/hr
b) 36 km/hr
c) 71.11 km/hr
d) 71 km/hr
e) 69.69km/hr