Question

A van moves for two hours with a constant speed of 36 km/h and then for another 1 hour 30 minutes with a constant speed of 84 km/h.

What distance did it go ?

What was the average speed over the whole journey ?

Answer 1

56.6km/hr

Explanation:

2 hours with a speed of 36km/hr is with a distance of (36×2) = 72km

1.5 hours with a speed of 84km/hr = 126km

Total distance = 72+126 = 198km

Average speed = 198/ total time taken = 198/3.5 = 56.6km/hr

Answer 2

56.57 km/h.

Explanation:

Distance traveled:

First, we need to convert the time into hours to have the same unit. 1 hour 30 minutes is equivalent to 1.5 hours.

The total time the van traveled is 2 hours + 1.5 hours = 3.5 hours.

The distance traveled during the first 2 hours is 36 km/h * 2 hours = 72 km.

The distance traveled during the next 1.5 hours is 84 km/h * 1.5 hours = 126 km.

The total distance traveled is 72 km + 126 km = 198 km.

Average speed over the whole journey:

The average speed is the total distance traveled divided by the total time traveled.

Average speed = Total distance traveled / Total time traveled = 198 km / 3.5 hours = 56.57 km/h.