Question 224981
it takes 15 workers to build 500 feet of fencing in 6 hours. At this rate, how many workers are needed to build 1000 feet of fencing in 9 hours
<pre>
It takes 15 workers to build 500 feet of fencing in 6 hours. 

Doubling the workers doubles the fencing in the same time.  Therefore,

it takes 30 workers to build 1000 feet of fencing in 6 hours.

Doubling the workers halves the time for the same amount of fencing. Therefore,

It takes 60 workers to build 1000 feet of fencing in 3 hours.

Using only one-third as many workers triples the time for the same
amount of fencing. Therefore,

It takes 20 workers to build 1000 feet of fencing in 9 hours.

Edwin</pre>