Question

You are trying to calculate the quickest route to drive to work. Your job is 7.5 miles from home. One option is to take the back roads to work. That route is calculated for driving at an average speed of 30 miles per hour. How long will it take you to get to work this way?

Answer 1

`0.25\ hour` or
`15\ min`

Explanation:

Let

d -----> the distance in miles

t -----> the time in hours

s -----> the speed in miles per hour

so

`s=(d)/(t)`

Solve for t

`t=(d)/(s)`

we have

`d=7.5\ mi`

`s=30\ mi/h`

substitute the values

`t=(7.5)/(30)`

`t=0.25\ hour`

Convert to minutes

`0.25\ hour=0.25*60=15\ min`