To go home on Christmas Eve, Vinay travels by Bus at 80 km/hr (yes Bangalore bus service is awesome) from office to Bangalore Airport for (13)3 of the total time. Then he travels by flight at 700 km/hr for next (13)3 of time to reach Chennai Airport. Then he takes a cab to his house which travels at 120 km/hr (since its midnight). Find his average speed for the entire journey.
300 km/hr
Let's assume the total time in the journey be T hours.
Trip 1
Office to Bangalore Airport
t1=T3
s1=80km/hr
Distance from office to bangalore airport d1=s.t=80
Trip 2
Bangalore airport to Chennai airport
t2=t3
s2 = 700 km/hr
distance from Bangalore airport to Chennai airport
d2 = s.t = 700
Trip 3
Chennai Airport to home
t2 = T/3
s3 = 120 km/hr
distance from Chennai Airport to home
d3 = s.t = 120
Average speed = 300 km/hr
Average speed = 300 km/hr