document.write( "Question 887261: Two mechanics worked on a car. The first mechanic worked for 10 hours, and the second mechanic worked for 5 hours. Together they charged a total of $1150 . What was the rate charged per hour by each mechanic if the sum of the two rates was $160 per hour? \n" ); document.write( "
Algebra.Com's Answer #536522 by algebrapro18(249)![]() ![]() ![]() You can put this solution on YOUR website! Lets start off by letting x be the first mechanics rate and y being the second mechanics rate. We know that the first mechanic worked 5 hours and that the second mechanic worked 10 hours and together they charged 1150. An equation to express this would be: \r \n" ); document.write( "\n" ); document.write( "5x+10y = 1150 \r \n" ); document.write( "\n" ); document.write( "We also know that together they charged 160/per hour. An equation to express this would be: \r \n" ); document.write( "\n" ); document.write( "x+y = 160 \r \n" ); document.write( "\n" ); document.write( "Now we can solve the second equation for x or the first mechanics rate. \r \n" ); document.write( "\n" ); document.write( "x+y = 160 \n" ); document.write( "x = 160 - y \r \n" ); document.write( "\n" ); document.write( "Now that we have an expression for x we can plug that back into the first equation and solve for y or how much the second mechanic charged. \r \n" ); document.write( "\n" ); document.write( "5x+10y=1150 plug in x =160-y \n" ); document.write( "5(160-y)+10y=1150 Distribute \n" ); document.write( "800 -5y+10y = 1150 Combine like terms \n" ); document.write( "800 +5y = 1150 Subtract 800 from both sides \n" ); document.write( "5y = 350 divide by 5 \n" ); document.write( "y = 70 \r \n" ); document.write( "\n" ); document.write( "So we know that the second mechanic charged $70/hour. We also know that(from our work before) that the first mechanic charges $160 - the rate the second mechanic charged. We know that's $70/hour so we can plug in and solve for the first rate. \r \n" ); document.write( "\n" ); document.write( "x = 160-y \n" ); document.write( "x = 160-70 \n" ); document.write( "x = 90 \r \n" ); document.write( "\n" ); document.write( "So we know that the first mechanic charged $90/hour and the second mechanic charged $70/hour. \n" ); document.write( " |