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(1) The cost of some books is60. Cost of every book is the same. If the booksellerdecreases the cost of the book by1, one gets 5 books more for the same amount.What is the cost of each book and how many books are purchased? |
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Answer» Let number of books = nCost of n books = 60Then,Cost of one book = 60/n If cost decrease by 1 rupees Number of books = n + 5Thus cost of each book will be = 60/(n + 5) 60/n - 1 = 60/(n + 5)(60-n)/n = 60/(n + 5)(60-n)(n + 5) = 60n60n + 300 - n^2 - 5n = 60nn^2 + 5n - 300 = 0n^2 + 20n - 15n - 300 = 0n(n + 20) - 15(n + 20) = 0(n - 15)(n + 20) = 0n = 15, - 20 Number of books = 15Cost of each book = 60/15 = Rs 4 |
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