document.write( "Question 808615: John and Mary are 300m apart on a straight road. They run at uniform speed. If they run towards each other, they will meet in 30 seconds. If they run in the same direction, John will overtake Mary in 70 seconds. Find their speeds of running. \n" ); document.write( "
Algebra.Com's Answer #487295 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
John and Mary are 300m apart on a straight road.
\n" ); document.write( " They run at uniform speed.
\n" ); document.write( " If they run towards each other, they will meet in 30 seconds.
\n" ); document.write( " If they run in the same direction, John will overtake Mary in 70 seconds.
\n" ); document.write( " Find their speeds of running.
\n" ); document.write( ":
\n" ); document.write( "let j = John's speed
\n" ); document.write( "let m = Mary's speed
\n" ); document.write( ":
\n" ); document.write( "Write a distance equation for each scenario
\n" ); document.write( "30(j + m) = 300; toward each other
\n" ); document.write( "70(j - m) = 300; same direction
\n" ); document.write( ":
\n" ); document.write( "30j + 30m = 300
\n" ); document.write( "70j - 70m = 300
\n" ); document.write( "multiply the 1st equation by 7, multiply the 2nd equation by 3
\n" ); document.write( "210j + 210m = 2100
\n" ); document.write( "210j - 210m = 900
\n" ); document.write( "-------------------adding eliminates m , find j
\n" ); document.write( "420j = 3000
\n" ); document.write( "j = 3000/420
\n" ); document.write( "j = 7.143 m/sec is John's speed
\n" ); document.write( ":
\n" ); document.write( "Find m
\n" ); document.write( "30(7.143) + 30m = 300
\n" ); document.write( "214.3 + 30m = 300
\n" ); document.write( "30m = 300 - 214,.3
\n" ); document.write( "30m = 85.7
\n" ); document.write( "m = 85.7/30
\n" ); document.write( "m = 2.857 m/sec is Mary's speed
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check this in the 2nd equation
\n" ); document.write( "70(7.143-2.857) =
\n" ); document.write( "70(4.386) = 300
\n" ); document.write( " \n" ); document.write( "
\n" );