document.write( "Question 1147091: A boy walked for 3 hours and cycled For 4 hours covering a distance of 80km.
\n" ); document.write( "A week later he walked for 2 hours and cycled for 5 hours covering 100km.
\n" ); document.write( "What were his average speed for walking and cycling, if his walking and cycling speed were constant \n" ); document.write( "
Algebra.Com's Answer #768398 by ankor@dixie-net.com(22740)\"\" \"About 
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A boy walked for 3 hours and cycled For 4 hours covering a distance of 80km.
\n" ); document.write( "A week later he walked for 2 hours and cycled for 5 hours covering 100km.
\n" ); document.write( "What were his average speed for walking and cycling, if his walking and cycling speed were constant
\n" ); document.write( ":
\n" ); document.write( "let w = his walking speed
\n" ); document.write( "let s = his cycling speed
\n" ); document.write( ":
\n" ); document.write( "Write a dist equation for each trip; dist = time * speed
\n" ); document.write( ":
\n" ); document.write( "walk dist + cycle dist = total dist
\n" ); document.write( "3w + 4s = 80
\n" ); document.write( "2w + 5s = 100
\n" ); document.write( "use elimination, multiply the 1st eq by 2 and the 2nd eq by 3
\n" ); document.write( "6w + 8s = 160
\n" ); document.write( "6w + 15s = 300
\n" ); document.write( "--------------- subtraction eliminates w, find
\n" ); document.write( "0 - 7s = -140
\n" ); document.write( "s = -140/-7
\n" ); document.write( "s = +20 mph is his cycling speed
\n" ); document.write( ":
\n" ); document.write( "Find w using the 2nd equation
\n" ); document.write( "2w + 5(20) = 100
\n" ); document.write( "2w = 100 - 100
\n" ); document.write( "w = 0 mph is the walking speed???
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