document.write( "Question 158729: gary drove to Sarnia. Part of the trip was along major highways and the rest was along country roads. the speed linit is 100km/h on the hgihgways and 80km/h on the other roads. he spent a total of 12 hours driving 1050 km. write a system of equations that would allow you to find how much time did he spend on each type of road. \n" ); document.write( "
Algebra.Com's Answer #117043 by ankor@dixie-net.com(22740)\"\" \"About 
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Part of the trip was along major highways and the rest was along country roads.
\n" ); document.write( " The speed limit is 100km/h on the highways and 80km/h on the other roads.
\n" ); document.write( "He spent a total of 12 hours driving 1050 km. Write a system of equations
\n" ); document.write( " that would allow you to find how much time did he spend on each type of road.
\n" ); document.write( ":
\n" ); document.write( "Let x = time on highway
\n" ); document.write( "Let y = time on country roads
\n" ); document.write( ":
\n" ); document.write( "The time equation:
\n" ); document.write( "x + y = 12
\n" ); document.write( "y = (12-x); use for substitution
\n" ); document.write( ":
\n" ); document.write( "The dist equation; dist = speed * time:
\n" ); document.write( "100x + 80y = 1050
\n" ); document.write( ";
\n" ); document.write( "Substitute (12-x) for y in the above equation; find x
\n" ); document.write( "100x + 80(12-x) = 1050
\n" ); document.write( "100x + 960 - 80x = 1050
\n" ); document.write( "100x - 80x = 1050 - 960
\n" ); document.write( "20x = 90
\n" ); document.write( "x = \"90%2F20\"
\n" ); document.write( "x = 4.5 hrs at 100 km/hr
\n" ); document.write( "and
\n" ); document.write( "y = 12 - 4.5 = 7.5 hrs at 80 km/hr
\n" ); document.write( ";
\n" ); document.write( ":
\n" ); document.write( "Check solutions by finding the total dist:
\n" ); document.write( "100(4.5) + 80(7.5) =
\n" ); document.write( " 450 + 600 = 1050; \n" ); document.write( "
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