document.write( "Question 962934: Ben was in charge of ordering 35 pizzas for the office party. He ordered three types of pizza: cheese, pepperoni and supreme. The cheese cost $9, pepperoni $12 and supreme $15. He spent exactly twice as much on the pepperoni as he did on the cheese pizzas. If been spent a total of $420, how many pizzas of each type did he buy?
\n" ); document.write( "x+y+z=35
\n" ); document.write( "9x+12y+15z=420\r
\n" ); document.write( "\n" ); document.write( "x=? y=? z=? \n" ); document.write( "

Algebra.Com's Answer #588319 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
1. $\"x%2By%2Bz=35\"$
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\n" ); document.write( " $\"P=2C\"$
\n" ); document.write( " $\"12y=2%289x%29%7D%7D%0D%0A%7B%7B%7B12y=18x\"$ \r
\n" ); document.write( "\n" ); document.write( "2. $\"2y=3x\"$
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\n" ); document.write( " $\"9x%2B12y%2B15z=420\"$
\n" ); document.write( "3. $\"3x%2B4y%2B5x=140\"$
\n" ); document.write( "Multiplying eq. 1 by 5 and subtracting from eq. 3,
\n" ); document.write( " $\"3x%2B4y%2B5z-5x-5y-5z=140-175\"$
\n" ); document.write( " $\"-2x-y=-35\"$
\n" ); document.write( "Multiply by 3.
\n" ); document.write( " $\"-6x-3y=-105\"$
\n" ); document.write( "Substitute from eq. 2,
\n" ); document.write( " $\"-2%282y%29-3y=-105\"$
\n" ); document.write( " $\"-4y-3y=-105\"$
\n" ); document.write( " $\"-7y=-105\"$
\n" ); document.write( " $\"y=15\"$
\n" ); document.write( "Then,
\n" ); document.write( " $\"2%2815%29=3x\"$
\n" ); document.write( " $\"x=10\"$
\n" ); document.write( "And,
\n" ); document.write( " $\"10%2B15%2Bz=35\"$
\n" ); document.write( " $\"z=10\"$ \r
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