A car travels at 60 km/h for the first 40 minutes, at 75 km/h for the next 80 minutes and at 80 km/h for the next 12 minutes. What is the average speed (in km/h) of the car?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. .
Average speed = Total distance/Total time
Distance travelled in first 40 minutes = 60 × 40/60 = 40 km
Distance travelled in next 80 minutes = 75 × 80/60 = 100 km
Distance travelled in 12 minutes = 80 × 12/60 = 16 km
Total distance = 40 + 100 + 16 = 156 km
Total time = (40 + 80 + 12)/60 = 2.2 h
Average speed = 156/2.2 =