Question

A truck covered 2/7 of a journey at an average speed of 40

mph. Then, it covered the remaining 200 miles at another
average speed. If the average for the whole journey was 35
mph, what was the amount of time for the whole journey?
h

Answer 1

The amount of time for the whole journey is 8 hours.

Step-by-step explanation:

A truck covered 2/7 of a journey at an average speed of 40 mph. Representing 1 the total of the trip traveled, then the rest of the distance traveled is calculated as:
`1-(2)/(7) =(5)/(7)`

So if the truck covered the remaining 200 miles at
`(2)/(7)`, this means that
`(5)/(7)` of the trip represents the 200 miles. So, to calculate the total distance traveled by the truck, you apply the following rule of three: if
`(5)/(7)` of the route represents 200 miles, the integer 1 (which represents the total of the route), how many miles are they?

`miles=(1*200miles)/((5)/(7) ) =(7)/(5) *200 miles`

miles= 280

So the total distance traveled is 280 miles. Since speed is the relationship between the space traveled by an object and the time used for it (
`speed=(distance)/(time)`), then if the average of the entire trip was 35 mph and the distance traveled 280 miles, the time is calculated as:

`time=(distance)/(speed)=(280 miles)/(35 mph)`

time= 8 h

The amount of time for the whole journey is 8 hours.