document.write( "Question 207920: I am trying to help my daugther to solve this problem but I can't write an equation for this problem.
\n" ); document.write( "\"It takes 5 min. to prepare a hamburger with extra 2 minutes to serve it, and 7 minutes to prepare a chicken sandwich with extra 1 min. to serve it. How many sandwiches can be prepared spending 42 minute in preparation and 15 minutes on serving?\" \n" ); document.write( "
Algebra.Com's Answer #157273 by ankor@dixie-net.com(22740)\"\" \"About 
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\"It takes 5 min. to prepare a hamburger with extra 2 minutes to serve it,
\n" ); document.write( " and 7 minutes to prepare a chicken sandwich with extra 1 min. to serve it.
\n" ); document.write( " How many sandwiches can be prepared spending 42 minute in preparation and 15 minutes on serving?\"
\n" ); document.write( ":
\n" ); document.write( "Let h = no. of hamburgers
\n" ); document.write( "Let c = no. of chicken sand
\n" ); document.write( ";
\n" ); document.write( "Prepare equation:
\n" ); document.write( "5h + 7c = 42
\n" ); document.write( ":
\n" ); document.write( "Serve equation
\n" ); document.write( "2h + 1c = 15
\n" ); document.write( "Arrange for substitution
\n" ); document.write( "1c = 15 - 2h
\n" ); document.write( "c = (15-2h)
\n" ); document.write( ":
\n" ); document.write( "Substitute (15-2h) for c in the 1st equation
\n" ); document.write( "5h + 7(15-2h) = 42
\n" ); document.write( "5h + 105 - 14h = 42
\n" ); document.write( "5h - 14h = 42 - 105
\n" ); document.write( "-9h = -63
\n" ); document.write( "h = \"%28-63%29%2F%28-9%29\"
\n" ); document.write( "h = +7 hamburgers
\n" ); document.write( "and
\n" ); document.write( "15 - 2(7) = 1 chicken sandwich
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solutions in the serve equation
\n" ); document.write( "2(7) + 1(1) = 15 min \n" ); document.write( "
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