document.write( "Question 169925: With an 18km/h tail wind a crow flies to a pond in 18 minutes. Find the crow's speed ( still in the air) if the return trip, with the head wind requires 46 minutes. \n" ); document.write( "
Algebra.Com's Answer #125368 by Alan3354(69443)\"\" \"About 
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With an 18km/h tail wind a crow flies to a pond in 18 minutes. Find the crow's speed ( still in the air) if the return trip, with the head wind requires 46 minutes.
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\n" ); document.write( "C = crow's airspeed
\n" ); document.write( "W = wind speed
\n" ); document.write( "Going downwind, the ground speed is the sum of the 2. Going upwind, it's the difference.
\n" ); document.write( "The time is the distance, s, divided by the ground speed, or
\n" ); document.write( "t = s/v (s is distance, v = ground speed)
\n" ); document.write( "Going with the wind:
\n" ); document.write( "18 = s/(C+W) = s/(C+18)
\n" ); document.write( "Going against the wind:
\n" ); document.write( "46 = s/(C-W) = s/(C-18)
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\n" ); document.write( "s = 18C + 324
\n" ); document.write( "s = 46C - 468
\n" ); document.write( "Subtract
\n" ); document.write( "0 = -28C + 792
\n" ); document.write( "28C = 792
\n" ); document.write( "C = 792/28 = 198/7 km/hr
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\n" ); document.write( "The distance can be solved for also, but if you have this on a test and time is limited, don't waste time doing that. Give them what is asked for and go on to the next problem.\r
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