A person runs at an average speed of 20 km/h for 30 minutes and cycles at a speed of 32 km/h for 1 hour 15 minutes. Calculate the average speed (in km/h, rounded off to 1 decimal place).
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 28.6.
Average Speed = Total Distance/total time
The average speed of a person while running = 20 km/h
Time taken by the person in running = 30 minutes = 1/2 h
The average speed of a person while cycling = 32 km/h
Time taken by the person in cycling = 1 hour 15 minutes = 5/4 h
Total distance = (20 × 1/2) + (32 × 5/4) = 50 km
Total time = 1/2 + 5/4 = 7/4 h
Average speed = 50/(7/4) = 28.6 km/h