Question

Tony completed a 720 km journey with an average speed of 90 km/h for the first 285 km he travelled at an average speed of 95 Km/h what was the average speed for the remaining journey

Answer 1

`Speed = 87 km/h`

Step-by-step explanation:

Given

Total Distance = 720km

Average Speed = 90km/h

Average Speed (285km) = 95km/h

Required

Determine the average speed for the rest of the journey

First we need to determine the time taken to complete the journey using

`Speed = (Distance)/(Time)`

`90 = (720)/(Time_1)`

Make Time the subject of formula

`Time_1 = (720)/(90)`

`Time_1 = 8 hour`

Next, we determine the time taken to complete 285km of the journey using

`Speed = (Distance)/(Time)`

`95 = (285)/(Time_2)`

Make Time the subject of formula

`Time_2 = (285)/(95)`

`Time_2 = 3 hours`

The difference between these calculated times is the time taken to complete the rest of the journey

`Time = Time_1 - Time_2`

`Time = 8\ hour - 3\ hour`

`Time = 5\ hour`

Also, we need to calculate the distance of the rest of the journey

`Distance = 720\ km - 285\ km`

`Distance = 435\ km`

The average speed can then be calculated;

`Speed = (Distance)/(Time)`

`Speed = (435)/(5)`

`Speed = 87 km/h`

Hence, the average speed of the rest of the journey is 87km/h