Question

Henry knows it takes approximately 4 hours to drive from Madison to Des Moines, a distance of about 275 miles. What must his average speed be to drive the distance in 4 hours? If the highway speed limit is 65 miles per hour, can he make it in this amount of time without breaking the law?

Answer 1

To find the average speed in miles per hour:


`(275)/(4) =68.75`

So he would need to drive at an average speed of 68.75 miles per hour in order to make it to Des Moines in 4 hours.

If the speed limit is 65, Henry better keep an eye out for Highway Patrol, since he MUST break the speed limit in order to average 68.75 miles per hour. (So, yeah, he'll be breaking the law.)