document.write( "Question 886737: Maria and Jose invested $20 in drink mix,sugar, and paper cups and opened a stand in front of their house one hot summer day. After four hours of business,they had collected $24.Assume that they sell the drinks at the same rate all day.\r
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\n" ); document.write( "\n" ); document.write( "For the formula,define a variable for the number of hours of the sale and use this variable to write a rule for their profit. \n" ); document.write( "
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they invested $20 in material.
\n" ); document.write( "after 4 hours they sold $24.00 worth.
\n" ); document.write( "let x = sales per hour.
\n" ); document.write( "you get:
\n" ); document.write( "4x = 24
\n" ); document.write( "solve for x to get:
\n" ); document.write( "x = 6
\n" ); document.write( "they are selling at the rate of 6 dollars per hour.
\n" ); document.write( "in an 8 hour day, they will have sold 8 * 6 = 48 dollars worth of good.
\n" ); document.write( "their profit at the end of the day would be equal to 48 - 20 = 28 dollars.
\n" ); document.write( "the formula for profit after x hours would be:
\n" ); document.write( "p = 6x - 20
\n" ); document.write( "the 20 is a fixed cost.
\n" ); document.write( "the 6x is the revenue that they earn for x hours of work.
\n" ); document.write( "profit is equal to revenue minus cost.\r
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\n" ); document.write( "\n" ); document.write( "there would be a limit to the number of hours for 20 dollars worth of material since eventually they would run out of material to sell.
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