Question

If the price of a book is reduced by Rs. 5, a person can buy 5 more books for Rs. 300. Find the original list price of the book.

Answer 1

Let the original list price of the book be Rs. x.

Therefore, number of books bought for Rs. 300 = $\frac{300}{x}$

Reduced list price of the book = Rs. (x-5)

Therefore, number of books bought for Rs. 300 = $\frac{300}{x-5}$

Given that,

$\frac{300}{x-5}-\frac{300}{x}=5$

$\frac{1500}{x^2-5x}=5$

$x^2-5x-300=0$

$(x-20)(x+15)=0$

$x=20$

Hence, the list price of the book is Rs. 20.