document.write( "Question 37629: A farmer has $3600 to spend on fencing for three adjoining rectuangular pastures, all with the same dimensions. a local contracting company tells the farmer that they can build the fence for $6.25/m. What is the largest total area that the farmer can have fenced for that price? \n" ); document.write( "
Algebra.Com's Answer #23236 by josmiceli(19441) You can put this solution on YOUR website! the fields would look like 3 adjoining rectangles \n" ); document.write( "with $3600 to spend and and a cost of $6.25/m, the farmer can \n" ); document.write( "afford 3600/6.25 = 576 m of fence \n" ); document.write( "He needs 4 north-south lengths and 2 east-west lengths (for example) \n" ); document.write( "in order to enclose 3 rectangular fields \n" ); document.write( "All these lengths will add up to 576 m. \n" ); document.write( " \n" ); document.write( "The area enclosed is x times y \n" ); document.write( " \n" ); document.write( "solve for y in the 1st equation \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "substitute this in equation 2 \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "graph the equation \n" ); document.write( " \n" ); document.write( "I'll guess the x value where the graph is a max is 144 \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "factor out 144^2 \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "The way to test this is to increase 144 a little, test it in the equation \n" ); document.write( "then decrease 144 a little and test it in the equation \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "since the area is a little bit less than 10368 on either side \n" ); document.write( "of x = 144, then this is the max. \n" ); document.write( "The largest Area that can be enclosed is 10368 \n" ); document.write( "---------------------------- \n" ); document.write( "check \n" ); document.write( "If x = 144, find y \n" ); document.write( "xy = 10368 \n" ); document.write( "y = 10368/144 \n" ); document.write( "y = 72 \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "OK \n" ); document.write( " |