Math CentralQuandaries & Queries


Question from Shanda, a student:

Paul and Charlene are 420 miles apart. They start toward each other with Paul driving 16 miles per hour faster than Charlene. They meet in 5 hours. Find Charlene's speed.

Hi Shanda.

If the gap between them starts at 420 miles and 5 hours later it is zero, then the gap is shrinking at a rate of 420/5 = 84 mph.

Since they are moving towards each other, both of their speeds are contributing to this gap-closing speed, so
P + C = 84

And the difference of their speeds is given to you:
P - C = 16.

Use these two equations to find the answer to your question.

Stephen La Rocque.

About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS