Elizabeth uses $3.00 worth of ingredients to make a  bag of granola.  She makes 20 bags and sells them for $6.00 a bag at the farmer's market.  An hour before closing, she has sold 15 bags and marks the remaining 5 bags down to $4.00 and sells them soon after.  What is her net profit?
She uses $3.00 of ingredients per 1 bag of granola and she makes 20 bags so she spends 3*20 = $
<gadget id="calculator">3*20</gadget>
<output>60</output>
60.00 on ingredients.
She sells 15 bags for $6.00 so she makes 15*6 = $
<gadget id="calculator">15*6</gadget>
<output>90</output>
90.00.
She sells her last 5 bags for $4.00 so she makes 5*4 = $
<gadget id="calculator">5*4</gadget>
<output>20</output>
20.00.
She made $90.00 and $20.00 for a total of 90+20 = $
<gadget id="calculator">90+20</gadget>
<output>110</output>
110.00.
She made $110.00 but spent $60.00 on ingredients so her net profit is 110-60 = $
<gadget id="calculator">110-60</gadget>
<output>50</output>
50.00.

<result>50</result>