Question

An automobile driver traveled the first part of a 400 mile trip at a average rate of 50 miles per hour.Upon reaching an interstate route his average speed increased to 60 miles per hour his total travel time was 7 hours how far had he traveled when reached the interstate route

Answer 1

The distance travelled is 100 miles

Step-by-step explanation:

We are given the total distance = 400 miles and total time taken = 7 hours

Given the average rate till interstate route is reached = 50 miles per hour and then rate is increased to 60 miles per hour till end of the trip.

Let x be the distance from starting till interstate route

so time taken is given by
`(x)/(50)`

and time taken for rest of the journey =
`\frac{(400-\mathrm{x})}{60}` as total distance = 400

Since, total time for journey = 7 hours ,

we get equation

`\left((x)/(50)+((400-x))/(60)\right)=7`

=> 60x + 20000 - 50x = 21000

which gives x = 100 which is the required answer