A cab driver drives from the airport

Question

 

Full question

A cab driver drives from the airport to a passenger’s home at an average speed of 60 miles per hour. After the pickup, the cab driver returns with the passenger along the same route to the airport at an average speed of 45 miles per hour. The road trip takes 2.1 hours. What is the driver’s average speed throughout the entire trip? Round your answer to the nearest hundredth.

Answer 1

Distance is x

a= time to go

b=time back.

speed* time=distance

60*a=x

45*b=x

 

a= x/60

b=x/45

total time = a+b= x/60+x/45= 7x/180 = 2.1

So, x = 2.1*180/7 = 54

total distance = x+x= 108

average speed = total dist/total time = 108/2.1 = 51.43