document.write( "Question 365519: A motorboat has a four-hour supply of gasoline. How far from the marina can it travel if the rate going out against the current is 20 mi/h and the rate coming back with the current is 30 mi/h? \n" ); document.write( "

Algebra.Com's Answer #260629 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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A motorboat has a four-hour supply of gasoline.
\n" ); document.write( " How far from the marina can it travel if the rate going out against the
\n" ); document.write( " current is 20 mi/h and the rate coming back with the current is 30 mi/h?
\n" ); document.write( ":
\n" ); document.write( "Let d = the one-way distance (dist from marina)
\n" ); document.write( "Write a time equation: time = dist/speed
\n" ); document.write( ":
\n" ); document.write( "out time + return time = 4 hrs
\n" ); document.write( " $\"d%2F20\"$ + $\"d%2F30\"$ = 4
\n" ); document.write( "multiply by 60, to clear the denominators, results:
\n" ); document.write( "3d + 2d = 60(4)
\n" ); document.write( "5d = 240
\n" ); document.write( "d = $\"240%2F5\"$
\n" ); document.write( "d = 48 miles
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "see if that's true, find the time each way
\n" ); document.write( "48/20 = 2.4 hrs
\n" ); document.write( "48/30 = 1.6 hrs
\n" ); document.write( "----------------
\n" ); document.write( "totals: 4.0 hrs; confirms our solution of 48 mi \n" ); document.write( "

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