Abdul, while driving to school, computes the average speed for his trip to be 20 km h-1. On his return trip along the same route, there is less traffic and the average speed is 30 km h-1. What is the average speed for Abdul’s trip?
Let, the school is at a distance of x km
Suppose the time taken while driving to school is t1
Given,
Average speed = 20 km/h
Speed =
20 =
Time taken, t1 = (1)
on returning from the trip the average speed is 30 km/h
Let, the time taken for the return trip is t2
Speed =
30 =
So, Time taken, t2 = (2)
Now, total distance of the whole trip from going to trip to returning back to school is:
Total distance = x + x
= 2x Km (3)
Time taken = +
=
=
= (4)
Now, we will calculate the average speed of the whole trip:
Average speed =
=
= 24 km/h
Therefore, the average speed for Abdul’s whole trip from going from to school to return back is 24 Km/h.