Question

A car travels up a hill at a constant speed of 37 km/h and returns down the hill at a constant speed of 66 km/h. Calculate the average speed for the whole trip

Answer 1

Answer:

The average speed is the ratio of total traveled distance to total time taken.

Let d be the total distance traveled by the car.

Thus distance traveled in each journey is d/2.

So, the time taken for going up the hill is t

1

=

v

1

(d/2)

=

37

d/2

=

74

d

Time taken for going down the hill is t

2

=

66

(d/2)

=

132

d

Thus, average speed is v

avg

=

t

1

+t

2

L

=

(L/74+L/132)

L

=47.4km