Firm A's revenues are described by the equation Ra = 17.12x and its costs by Ca = 12.87x + 2400.
Firm B's revenues are described by the equation Rb = 13.27x and its costs by Cb = 8.77x + 1500.
(x denotes the quantity of sales).
If A's volume of sales increases from 1000 to 2000 over the same period that B's volume increases from 2000 to 3000, the percent increase in profits for the firm with the biggest dollar increase in profits is  Choose one:
A) 20%  B) 30%  C) 60%  D) 50%  E) 33%
Because you need the % increase in profit.   The increase in profit = 4.5 * 1000 (increase in the units from 2000 to 3000)   The original profit = 4.5*2000 - 1500 (initially 2000 units were sold)   % increase = (4.5 * 1000)/(4.5*2000 - 1500) * 100= 
<gadget id="calculator">(4.5 * 1000)/(4.5*2000 - 1500) * 100</gadget>
<output>60</output>
60%   ANSWER:60%
<result>C</result>
Firm A's revenues are described by the equation Ra = 17.12x and its costs by Ca = 12.87x + 2400.
Firm B's revenues are described by the equation Rb = 13.27x and its costs by Cb = 8.77x + 1500.
(x denotes the quantity of sales).
If A's volume of sales increases from 1000 to 2000 over the same period that B's volume increases from 2000 to 3000, the percent increase in profits for the firm with the biggest dollar increase in profits is