A driver increases the speed of his vehicle by 5 km/h after every hour. If the initial
speed of the vehicle was 75 km/h, then what was the average speed of the vehicle in a
journey of 4 hours?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 82.5 km/h.
The initial speed of the vehicle = 75km/h
Then the driver increases the speed of his vehicle by 5 km/h after every hour.
Speed in the first hour = 75km/h
Speed in the second hour = 75 + 5 = 80km/h
Speed in the third hour = 80 + 5 = 85km/h
Speed in the fourth hour = 85 + 5 = 90km/h
Average speed of the vehicle in the journey = (75 + 80 + 85 + 90) ÷ 4 = 330 ÷ 4 = 82.5km/h