document.write( "Question 591922: how to solve this problem a speed boat travels at a rate of 20 KPH in still water. It travels 55 Km. upstream in the same time that it travels 90 KM downstream. What is the rate of the current \n" ); document.write( "
Algebra.Com's Answer #375781 by stanbon(75887)\"\" \"About 
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how to solve this problem a speed boat travels at a rate of 20 KPH in still water. It travels 55 Km. upstream in the same time that it travels 90 KM downstream. What is the rate of the current
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\n" ); document.write( "Upstream DATA:
\n" ); document.write( "rate = (20-c)km/h ; distance = 55 km ; time = d/r = 55/(20-c) hrs.
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\n" ); document.write( "Downstream DATA:
\n" ); document.write( "rate = (20+c)km/h ; distance = 90 km ; time = 90/(20+c) hrs.
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\n" ); document.write( "Equation:
\n" ); document.write( "time up = time down
\n" ); document.write( "55/(20-c) = 90/(20+c)
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\n" ); document.write( "55*20 + 55c = 90*20 - 90c
\n" ); document.write( "145c = 35*20
\n" ); document.write( "c = (7/29)*20
\n" ); document.write( "c = 140/29 = 4.83 km/h (rate of the current)
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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