document.write( "Question 923544: it takes 8 tractors 12 days to plough a field, how long would it take 15 tractors?\r
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Algebra.Com's Answer #560108 by ptaylor(2198)\"\" \"About 
You can put this solution on YOUR website!
Let x=amount of time it takes 15 tractors to plow the field
\n" ); document.write( "If it takes 8 tractors 12 days to plow a field, then it will take 1 tractor 8*12 or 96 days to plow a field. So the rate at which a tractor plows is 1/96 of a field/day and the rate at which 15 tractors plows is 15/96 of a field/day.
\n" ); document.write( "So our equation to solve is:
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\n" ); document.write( "(15/96) of a field per day times x days =1 field plowed. or
\n" ); document.write( "(15/96)x=1 multiply each side by 96
\n" ); document.write( "15x=96
\n" ); document.write( "x=6.4 days\r
\n" ); document.write( "\n" ); document.write( "Another way:
\n" ); document.write( "It takes 8*12 =96 tractor-days to plow the field
\n" ); document.write( "1 tractor takes 96 days
\n" ); document.write( "2 tractors take 96/2=48 days
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\n" ); document.write( "8 tractors take 96/8=12 days
\n" ); document.write( "15 tractors take 96/15=6.4 days\r
\n" ); document.write( "\n" ); document.write( "Hope this helps---ptaylor\r
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