Question 1157135
.
<pre>

The revenue is R(x) = x*(10-x).


It is a parabola opened downward, with x-intercepts at 0 and 10.


The maximum is achieved  at x= 5, exactly half way between x-intercepts.


So, the price of $5 per lamp will provide maximum revenue.    <U>ANSWER</U>
</pre>

Solved.