 |
| ||
| |||
|
| Math Central | Quandaries & Queries |
|
Question from Nancy, a teacher: Peter takes 15 minutes longer to mow the lawn by himself than Charles does. Together they can mow the lawn in 18 minutes. How long would it take Charles to mow the lawn by himself? |
Hi Nancy.
Let P = the time that Peter takes to mow one lawn.
Let C = the time that Charles takes to mow one lawn.
After 18 minutes, Charles has mowed 18/C lawns.
After 18 minutes, Peter has mowed 18/P lawns.
After 18 minutes mowing together, the team has mowed 18/C + 18/P lawns.
After 18 minutes mowing together, the team has mowed 1 lawn (this is given).
Thus, 18/C + 18/P = 1.
When mowing a lawn, Peter takes 15 minutes longer than Charles, so P = 15 + C.
Can you use the substitution method and solve these two equations for C?
Cheers,
Stephen La Rocque.
| ||
| ||
| ||
 |
 |
|
Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.