document.write( "Question 237017: Jack and Jill live at opposite ends of the same street. Jack wanted to deliver a box at Jill's house, and Jill wanted to leave some flowers at Jack's house. They started at the same moment, each walking at a constant speed. They met the first time 300 meters from Jack's house. On their return trip, they met 400 meters from Jill's house. How long is the street? \n" ); document.write( "
Algebra.Com's Answer #174630 by ankor@dixie-net.com(22740)\"\" \"About 
You can put this solution on YOUR website!
Jack and Jill live at opposite ends of the same street.
\n" ); document.write( " Jack wanted to deliver a box at Jill's house, and Jill wanted to leave some flowers at Jack's house.
\n" ); document.write( "They started at the same moment, each walking at a constant speed.
\n" ); document.write( "They met the first time 300 meters from Jack's house.
\n" ); document.write( "On their return trip, they met 400 meters from Jill's house.
\n" ); document.write( "How long is the street?
\n" ); document.write( ":
\n" ); document.write( "Let d = length of the street\r
\n" ); document.write( "\n" ); document.write( "Jill>-----(d-300)------|*|-----300------< Jack
\n" ); document.write( "First meeting Jill walks (d-300m); Jack walks 300M
\n" ); document.write( ":
\n" ); document.write( "jack>-----------400---------|*|--(d-400)-< Jill
\n" ); document.write( "Second meeting:
\n" ); document.write( " Jack walks: d-300) + 400 = (d+100)
\n" ); document.write( " Jill walks: 300 + (d-400)= (d-100)
\n" ); document.write( ":
\n" ); document.write( "The ratio of their walking distances will be the same, write a ratio equation:
\n" ); document.write( "\"Jill%2Fjack\":\"%28%28d-300%29%29%2F300\" = \"%28%28d-100%29%29%2F%28%28d%2B100%29%29\"
\n" ); document.write( "Cross multiply
\n" ); document.write( "(d-300)(d+100) = 300(d-100)
\n" ); document.write( "d^2 - 200d - 30000 = 300d - 30000
\n" ); document.write( ":
\n" ); document.write( "d^2 - 200d - 300d - 30000 + 30000 = 0
\n" ); document.write( ":
\n" ); document.write( "d^2 - 500d = 0
\n" ); document.write( "Factor out d
\n" ); document.write( "d(d - 500) = 0
\n" ); document.write( "d = 500 meters is the length of the street
\n" ); document.write( " \n" ); document.write( "
\n" );