document.write( "Question 1179660: A motorboat traveling with the current went 42 mi in 3.5 h. Traveling against the current, the boat went 18 mi in 3 h. Find the rate of the boat in calm water and the rate of the current. \n" ); document.write( "

Algebra.Com's Answer #809223 by mananth(16946) $\"\"$ $\"About$

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boat speed= x km/h
\n" ); document.write( "current speed= y km/h
\n" ); document.write( "with current speed= (x+y)
\n" ); document.write( "against current speed (x-y)
\n" ); document.write( "d= 42 with current
\n" ); document.write( "42 / (x+y) = 3.5
\n" ); document.write( "divide by 3.5
\n" ); document.write( "12 / (x+y) = 1
\n" ); document.write( "(x+y) = 12 ............1
\n" ); document.write( "d= = 18 against current
\n" ); document.write( "18/(x-y) = 3
\n" ); document.write( "divide by 3
\n" ); document.write( "6 /(x-y) = 1
\n" ); document.write( " x - y = 6 .............2
\n" ); document.write( "add up (1) & (2)
\n" ); document.write( "2 x = 18
\n" ); document.write( "/ 2
\n" ); document.write( "x= 9 mph speed of boat in still water
\n" ); document.write( "plug value of x in (1)
\n" ); document.write( "we get y= 3 mph speed of current
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