document.write( "Question 867179: A shopkeeper buys a certain number of books for Rs.720.if the cost per book was Rs.5 less, thenumber of books that could be bobought for Rs.720 could be 2 more.taking the original cost of each book to be Rs.x, write an equation and solve it. \n" ); document.write( "
Algebra.Com's Answer #522809 by dkppathak(439)\"\" \"About 
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A shopkeeper buys a certain number of books for Rs.720.if the cost per book was Rs.5 less, then umber of books that could be bought for Rs.720 could be 2 more.taking the original cost of each book to be Rs.x, write an equation and solve it.
\n" ); document.write( "Answer :
\n" ); document.write( "let cost of 1 book purchased is Rs X
\n" ); document.write( "number of books purchased for Rs 720 will be = 720/x
\n" ); document.write( "as per given conditions
\n" ); document.write( "if cost of one book is reduced by RS 5 each
\n" ); document.write( "than new cost of 1 book will be = Rs (X-5)
\n" ); document.write( "number of books will be =720/(x-5)
\n" ); document.write( "if cost reduced RS 5 for each books than 2 books will purchased more
\n" ); document.write( "720/(x-5)-720/x=2
\n" ); document.write( "720x-720(x-5)/x(x-5) =2
\n" ); document.write( "720(x-x+5)/x^2-5x=2
\n" ); document.write( "720x5 =2(x^2-5x)
\n" ); document.write( "1800=X^2-5x
\n" ); document.write( "X^2-5x-1800=0
\n" ); document.write( "by splitting middle term
\n" ); document.write( "X^2-45x+40x-1800 =0
\n" ); document.write( "x(x-45)+40(x-45)=0
\n" ); document.write( "(x-45)(x+40)=0
\n" ); document.write( "x=45 or x=-40
\n" ); document.write( "neglecting -40 as cost of book can not be negative so cost of book will be Rs 45 each
\n" ); document.write( "therefor cost of 1 book will be Rs 45 each
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