Reshma covers 45 km at a speed of 15 km/h by bicycle, 80 km at a speed of 40 km/h by car, and another 6 km at a speed of 2 km/h on foot. Find her average speed for the whole journey (correct to 2 decimal places).
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 16.38 km/h
Average speed = Total distance travelled / Total time taken
Total distance = 45 km + 80 km + 6 km
Total distance = 131 km
Time taken while bicycling = 45 km / 15 km/h = 3 hours
Time taken while driving = 80 km / 40 km/h = 2 hours
Time taken on foot = 6 km / 2 km/h = 3 hours
Total time = 3 hours + 2 hours + 3 hours = 8 hours
Average speed = 131 km / 8 hours = 16.375 km/h
Average speed (correct to 2 decimal places) = 16.38 km/h