document.write( "Question 1051684: a truck with a heavy load drove from boston to New york at a speed of 40 mph. After unloading, it returned from New york to boston at a speed of 60 mph. What was the average speed for the whole trip \n" ); document.write( "

Algebra.Com's Answer #667135 by stanbon(75887) $\"\"$ $\"About$

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a truck with a heavy load drove from boston to New york at a speed of 40 mph. After unloading, it returned from New york to boston at a speed of 60 mph. What was the average speed for the whole trip
\n" ); document.write( "B to NY DATA:
\n" ); document.write( "rate = 40 mph ; distance = x miles ; time = d/r = x/40 hrs
\n" ); document.write( "-----
\n" ); document.write( "NY to B DATA:
\n" ); document.write( "rate = 60 mph ; distance = x miles ; time = d/r = x/60 hrs
\n" ); document.write( "----
\n" ); document.write( "Average speed = (total distance)/(total time) = 2x/(x/40 + x/60)
\n" ); document.write( "-----
\n" ); document.write( "= (2x)/(60x + 40x)/(40*60)
\n" ); document.write( "----
\n" ); document.write( "= (2x)/[100x/2400]
\n" ); document.write( "-----
\n" ); document.write( "= 2/(1/24)
\n" ); document.write( "----
\n" ); document.write( "= 48 mph
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\n" ); document.write( "Cheers
\n" ); document.write( "Stan H.
\n" ); document.write( "------------ \n" ); document.write( "

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