document.write( "Question 134362This question is from textbook algebra
\n" ); document.write( ": 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 20mi/h and the rate the rate coming back with the current is 30mi/h?
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Algebra.Com's Answer #98266 by edjones(8007)\"\" \"About 
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rt=d r=rate t=time d=distance
\n" ); document.write( "Let a=time going against the current, w=time going with the current
\n" ); document.write( "The distance up the river equals the distance down.
\n" ); document.write( "M) a+w=4
\n" ); document.write( "N) 20a=30w
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\n" ); document.write( "M) 30a+30w=120 multiply each side by 30.
\n" ); document.write( "N) 20a-30w=0
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\n" ); document.write( "==>50a=120
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\n" ); document.write( "a=120/50=12/5 hrs
\n" ); document.write( "w=4- 12/5 =8/5 hrs
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\n" ); document.write( "20*12/5=48 mi Ans.
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\n" ); document.write( "Check:
\n" ); document.write( "30*8/5=48 mi
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\n" ); document.write( "Ed\r
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