Question

Q.25. If the price of a book is reduced by 5, a person can
buy 5 more books for 300. Find the original list price of the book. [Board Term-2 , 2012 set (17)].​

Answer 1

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

Number of books bought for Rs.300=

x

300

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

Number of books bought for Rs.300=

x−5

300

it is given that

x−5

300

−

x

300

=5

⇒

x(x−5)

300x−300x+1500

=5⇒

x

2

−5x

1500

=5

⇒x

2

−5x=300⇒x

2

−5x−300=0⇒x

2

−20x+15x−300=0

⇒(x−20)(x+15)=0⇒x=20orx=−15⇒x=20

hence, the list price of the book =Rs.20