Abdul, while driving to school, computes the average speed for his trip to be 20 km/h. On his return trip along the same route, there is less traffic and the average speed is 30 km /h. What is the average speed for Abdul’s trip?

Given:
– Speed during the trip to school = 20 km/h
– Speed during the return trip = 30 km/h

To determine the overall average speed, we use the formula:

Total average speed = Total distance / Total time

Assuming Abdul travels the same distance to and from school:

Calculation:
Let’s denote the distance to school as ‘D’.
– Time taken for the trip to school = Distance to school / Speed to school = D / 20
– Time taken for the return trip = Distance to school / Speed of return = D / 30

The total time for the entire trip:
Total time = Time to school + Time for return trip
Total time = D / 20 + D / 30

Now, the formula for total average speed:
Total average speed = Total distance / Total time

Substituting the expression for total time:
Total average speed = 2D / (D / 20 + D / 30)

Simplify the equation:
Total average speed = 2D / ((3D + 2D) / 60)
Total average speed = 2D / (5D / 60)
Total average speed = 120 / 5
Total average speed = 24 km/h

Hence, Abdul’s average speed for his entire round trip, accounting for both the journey to school and the return trip, is calculated to be 24 km/h. This indicates that considering his varying speeds in both directions, Abdul maintained an average speed of 24 km/h throughout the entire journey.