document.write( "Question 263150: If one walks 500 feet at 4 miles per hour walking to his/her destination and walks back 500 feet at 3 miles per hour... What is the average speed for the entire trip? How do you calculate it? \n" ); document.write( "
Algebra.Com's Answer #193904 by oberobic(2304)\"\" \"About 
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We know:
\n" ); document.write( "d = rt, where d=distance, r=rate, t=time
\n" ); document.write( "d = 500 ft
\n" ); document.write( "r = 4 miles per hr (going one way)
\n" ); document.write( "r = 3 miles per hr (going the other way)
\n" ); document.write( ".
\n" ); document.write( "We need to get everything into feet:
\n" ); document.write( "4 miles per hr = 4*5280 ft per mile = 21,120 ft per hr
\n" ); document.write( "3 miles per hr = 3*5280 ft per mile = 15,840 ft per hr
\n" ); document.write( ".
\n" ); document.write( "At 4 mph:
\n" ); document.write( "500 = 21120 t
\n" ); document.write( "t = .02367 hr
\n" ); document.write( ".
\n" ); document.write( "At 3 mph:
\n" ); document.write( "500 = 15840 t
\n" ); document.write( "t = .03156 hr
\n" ); document.write( ".
\n" ); document.write( "The total distance walked: 1000 feet
\n" ); document.write( "The total time: .02367 + .03156 = .05523 hrs
\n" ); document.write( "1000 = .05523 r
\n" ); document.write( "r = 18,106 feet/hr
\n" ); document.write( "dividing by 5,280 feet/mile we have
\n" ); document.write( "r = 4.329 miles per hr, which is the average rate
\n" ); document.write( ".
\n" ); document.write( "done. \n" ); document.write( "
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