A utility company has a coal-burning plant. Let percent be p,with 1≤p≤99, and a cost be C(p). The cost of removing p percent of smokestack pollutants is given by
C(p)=100000p/(100-p)
It is obvious that to remove 100% of pollutants has infinite cost, as in the denominator we get 1-1=0. Thus p≤99.
Currently state law requires that 70% of pollutants be removed. A legislator is proposing a new law, that 90% of pollutants be removed. How much addition cost will result?

Question

A utility company has a coal-burning plant.  Let percent be p,with 1≤p≤99, and a cost be C(p).  The cost of removing p percent of smokestack pollutants is given by
C(p)=100000p/(100-p)
It is obvious that to remove 100% of pollutants has infinite cost, as in the denominator we get 1-1=0.  Thus p≤99.
Currently state law requires that 70% of pollutants be removed.  A legislator is proposing a new law, that 90% of pollutants be removed.  How much addition cost will result?

anonymous · Answer

You're trying to find the additional cost, so, you're trying to find $$C(90) - C(70)$$
Just replace p in the formula with the value you want to find the cost for.

So...$$C(70) = \frac{1000000(70)}{(100-70)}$$