Question 133769
The amount of money the class makes is called the profit and profit is the difference between the money received, called revenue, and the cost of doing business, called cost.


{{{P=R-C}}}.


In this example, there is only one cost element, the truck rental of $150.  In other words, {{{C=150}}}  And there is only one revenue element, $15 for every ton of newspaper.  The total revenue is the number of tons of newspaper collected times $15, and if x represents the number of tons, 15x represents the revenue from x tons, so {{{R=15x}}}


So, substituting:


{{{P=15x-150}}}