Question

If the price of a book is reduced by rs 5 a person can buy 4 more books for rupees 600 find the orignal price of the book

Answer 1

Price of one book = x

No of books = y

So xy = 600

y = 600/x    ---------------(1)

Now price is reduced Rs. 5 and number of books increased by 4

(x - 5) (y + 4) = 600

xy + 4x - 5y - 20 = 600

4x - 5y = 20

4x - 5(600/x) = 20

4x² - 3000 = 20x

4x² - 20x = 3000

x² - 5x = 750

(x - 30) (x +20)

x = 30, -20

-ve can't be the price

So original price of the book = Rs. 30