A motorist travelled 48km at an average speed of 30km/h. If he made a returned journey at an average speed of 50km/h. Find the average speed of the whole journey.

Answer 1

To find the average speed of the whole journey, we need to find the total distance traveled and the total time taken.

The motorist traveled 48 km on the first leg of the journey at an average speed of 30 km/h. So, the time taken for this part of the journey can be found using the formula:

Time = Distance / Speed

Time 1 = 48 km / 30 km/h = 1.6 hours

On the return journey, the motorist traveled the same distance, 48 km, at an average speed of 50 km/h. So, the time taken for this part of the journey can be found using the same formula:

Time 2 = 48 km / 50 km/h = 0.96 hours

Now, to find the total time taken for the whole journey, we need to add the time taken for both parts:

Total Time = Time 1 + Time 2 = 1.6 hours + 0.96 hours = 2.56 hours

To find the average speed of the whole journey, we can use the formula:

Average Speed = Total Distance / Total Time

Total Distance = 48 km + 48 km = 96 km

Average Speed = 96 km / 2.56 hours ≈ 37.5 km/h

Therefore, the average speed of the whole journey is approximately 37.5 km/h.