document.write( "Question 419126: Carolina starts on a 58 mile trip on her moped at 20 mph. After a while the motor kicks out and she pedals the remainder of the trip at 12 mph. The entire trip took 3 1/2 hours. How far did Carolina travel when the motor on the moped quit running? \n" ); document.write( "

Algebra.Com's Answer #293151 by mananth(16946) $\"\"$ $\"About$

You can put this solution on YOUR website!
riding time =x
\n" ); document.write( "pedalling time = y\r
\n" ); document.write( "\n" ); document.write( "x+y = 7/2
\n" ); document.write( "2x+2y=7..............1\r
\n" ); document.write( "\n" ); document.write( "20x+12y=58...........2\r
\n" ); document.write( "\n" ); document.write( "...
\n" ); document.write( "
\n" ); document.write( "multiply (1)by -6
\n" ); document.write( "Multiply (2) by 1
\n" ); document.write( "-12 x + -12 y = -42
\n" ); document.write( "20 x + 12 y = 58
\n" ); document.write( "
\n" ); document.write( "Add the two equations
\n" ); document.write( "
\n" ); document.write( "8x=16
\n" ); document.write( "
\n" ); document.write( "/8
\n" ); document.write( "
\n" ); document.write( "x=2
\n" ); document.write( "
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "
\n" ); document.write( "2x+2y=7
\n" ); document.write( "4+2y=7
\n" ); document.write( "2y=7-4
\n" ); document.write( "2y=3
\n" ); document.write( "y=1.5
\n" ); document.write( "X=2
\n" ); document.write( "Distance = 2* 20 = 40 miles
\n" ); document.write( "it kicked out \n" ); document.write( "

\n" );