document.write( "Question 332537: A motor boat traveling with the current went 12 mi in 1 h. Against the current, it took 2 h to travel the same distance. Find the rate of the boat in calm water and the rate of the current. \n" ); document.write( "
Algebra.Com's Answer #238363 by ankor@dixie-net.com(22740)\"\" \"About 
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A motor boat traveling with the current went 12 mi in 1 h.
\n" ); document.write( " Against the current, it took 2 h to travel the same distance.
\n" ); document.write( " Find the rate of the boat in calm water and the rate of the current.
\n" ); document.write( ":
\n" ); document.write( "Let s = boat speed in calm water
\n" ); document.write( "Let c = rate of the current
\n" ); document.write( "then
\n" ); document.write( "(s-c) = effective speed upstream
\n" ); document.write( "and
\n" ); document.write( "(s+c) = effective speed downstream
\n" ); document.write( ":
\n" ); document.write( "Write a dist equation for each trip: dist = time * effective speed
\n" ); document.write( "1(s + c) = 12
\n" ); document.write( "2(s - c) = 12
\n" ); document.write( ":
\n" ); document.write( "On the first equation divide both sides by 1
\n" ); document.write( "On the second equation divide both sides by 2
\n" ); document.write( ":
\n" ); document.write( "s + c = 12
\n" ); document.write( "s - c = 6
\n" ); document.write( "------------adding, eliminates c, find s
\n" ); document.write( "2s = 18
\n" ); document.write( "s = 9 mph, boat speed in calm water
\n" ); document.write( "Find c
\n" ); document.write( "s + c = 12
\n" ); document.write( "9 + c = 12
\n" ); document.write( "c = 12 - 9
\n" ); document.write( "c = 3 mph is the current
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Check solutions in the original 2nd equation
\n" ); document.write( "2(9 - 3) = 12 \n" ); document.write( "
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