document.write( "Question 1066348: A carpenter orders 84 doors. He orders 3 times as many red doors as blue doors. How many blue doors does he order? \n" ); document.write( "

Algebra.Com's Answer #681528 by josmiceli(19441) $\"\"$ $\"About$

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[ blue doors ] / [ red doors ] = 1/3
\n" ); document.write( "Let $\"+x+\"$ = number of blue doors
\n" ); document.write( " $\"+84+-+x+\"$ = number of red doors
\n" ); document.write( "--------------------------------
\n" ); document.write( " $\"+x+%2F+%28+84+-+x+%29+=+1%2F3+\"$
\n" ); document.write( "Multiply both sides by $\"+3%2A%28+84+-+x+%29+\"$
\n" ); document.write( " $\"+3x+=+84+-+x+\"$
\n" ); document.write( " $\"+4x+=+84+\"$
\n" ); document.write( " $\"+x+=+21+\"$
\n" ); document.write( "and
\n" ); document.write( " $\"+84+-+x+=+84+-+21+\"$
\n" ); document.write( " $\"+84+-+x+=+63+\"$
\n" ); document.write( "---------------------
\n" ); document.write( "He orders 21 blue doors
\n" ); document.write( "----------------------
\n" ); document.write( "check:
\n" ); document.write( " $\"+21+%2F+63+=+1%2F3+\"$
\n" ); document.write( "Divide top and bottom of the left
\n" ); document.write( "side by $\"+21+\"$
\n" ); document.write( " $\"+1+%2F+3+=+1+%2F+3+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );