document.write( "Question 955181: If im doing a marathon for charity and every mile i run i earn 16$ every mile i bike i earn 12$. At the end of the marathon i ran and biked a total of 24 miles and earned 318$. How many miles did i run and how many miles did i bike?
\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #583443 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Ler $\"+r+\"$ = number of miles you run
\n" ); document.write( "Let $\"+b+\"$ = number of miles you bike
\n" ); document.write( "-----------------
\n" ); document.write( "(1) $\"+r+%2B+b+=+24+\"$
\n" ); document.write( "(2) $\"+16r+%2B+12b+=+318+\"$
\n" ); document.write( "------------------------
\n" ); document.write( "Multiply both sides of (1) by $\"+12+\"$
\n" ); document.write( "and subtract (1) from (2)
\n" ); document.write( "(2) $\"+16r+%2B+12b+=+318+\"$
\n" ); document.write( "(1) $\"+-12r+-+12b+=+288+\"$
\n" ); document.write( "-----------------------
\n" ); document.write( " $\"+4r+=+30+\"$
\n" ); document.write( " $\"+r+=+7.5+\"$
\n" ); document.write( "and, since
\n" ); document.write( "(1) $\"+r+%2B+b+=+24+\"$
\n" ); document.write( "(1) $\"+7.5+%2B+b+=+24+\"$
\n" ); document.write( "(1) $\"+b+=+16.5+\"$
\n" ); document.write( "-----------------
\n" ); document.write( "7.5 = number of miles you run
\n" ); document.write( "16.5 = number of miles you bike
\n" ); document.write( "------------
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+16r+%2B+12b+=+318+\"$
\n" ); document.write( "(2) $\"+16%2A7.5+%2B+12%2A16.5+=+318+\"$
\n" ); document.write( "(2) $\"+120+%2B+198+=+318+\"$
\n" ); document.write( "(2) $\"+318+%2B+318+\"$
\n" ); document.write( "OK \n" ); document.write( "

\n" );