document.write( "Question 414122: Two mechanics worked on a car. The first mechanic charged $45 per hour, and the second mechanic charged $85 per hour. The mechanics worked for a combined total of 20 hours, and together they charged a total of $1100 . How long did each mechanic work? \n" ); document.write( "

Algebra.Com's Answer #290468 by josmiceli(19441) $\"\"$ $\"About$

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Let $\"a\"$ = hours that 1st mechanic worked
\n" ); document.write( "Let $\"b\"$ = hours that 2nd mechanic worked
\n" ); document.write( "given:
\n" ); document.write( "(1) $\"45a+%2B+85b+=+1100\"$
\n" ); document.write( "(2) $\"a+%2B+b+=+20\"$
\n" ); document.write( "Multiply both sides of (2) by $\"45\"$ and
\n" ); document.write( "subtract (2) from (1)
\n" ); document.write( "(1) $\"45a+%2B+85b+=+1100\"$
\n" ); document.write( "(2) $\"-45a+-+45b+=+-900\"$
\n" ); document.write( " $\"40b+=+200\"$
\n" ); document.write( " $\"b+=+5\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"a+%2B+5+=+20\"$
\n" ); document.write( "(2) $\"a+=+15\"$
\n" ); document.write( "1st mechanic worked 15 hrs
\n" ); document.write( "2nd mechanic worked 5 hrs\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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