document.write( "Question 987556: last year, a farmer used 3 ploughs to plough a field in 17 hours. this year the same job must be done in 5 hours, how many ploughs will be needed? \n" ); document.write( "

Algebra.Com's Answer #608294 by josmiceli(19441) $\"\"$ $\"About$

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For last year, 1 plough would take 3
\n" ); document.write( "times as long, or:
\n" ); document.write( "1 plough plows a field in 51 hrs
\n" ); document.write( "51 ploughs plow a field in 1 hr
\n" ); document.write( "----------------------------
\n" ); document.write( "You only need 1/5 as many ploughs if
\n" ); document.write( "you want to take 5 times as long, so
\n" ); document.write( " $\"+51%2F5+\"$ plows plough the field in $\"+5+\"$ hrs
\n" ); document.write( " $\"+10+\"$ plows won't quite do it, they will
\n" ); document.write( "take $\"+5.1+\"$ hrs, so $\"+11+\"$ ploughs are needed
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