Question

by increasing the list price of a book by rs 10 a person can buy 10 less books for RS 1200. find the list price of the book

Answer 1

Answer:

Step-by-step explanation:

By increasing the list price of a book by Rs.10, a person can buy 10 books less for Rs.1200. Find the original list price of the book?

Let original book price=X

Number of books that can be bought in 1200 =1200/x

Suppose price increases by 10. New price=x+10

No of books that can be bought in new price= 1200/(x+10)

Now, this number is 10 less than the no of books that can be bought in 1200 at ‘x’ price.

So, 1200/x= 1200/(x+10) + 10

Simplifying the above we get

X^2 +30x -1200=0

This is a quadraatic equation having two solutions, 30 & -40. Ignoring negative value the answer is x=30

So orinal book price is Rs 30

Answer 2

Answer:

Let the price of each book is x and he can buy y books

Step-by-step explanation:

So, xy=1200

Now

Price is (x+10) and he can buy (y-10) books

(x+10)(y-10)=1200

10y-10x=100

y = 10+x

x(10+x)=1200

x^2+10x-1200=0

(x-30)(x+40)=0

x=30

and y=40