Question

By increasing the list price of a book by ₹10 a person can buy 10less for books for ₹1200.find the original price of the book

Answer 1

Let no. Of books he purchase=x
And price of 1 book =y
x*y=1200
Also
(x-10)(y+10)=1200
=xy+10x-10y-100=1200
1200+10x-10y=1200+100
10x-10y=100
x=10+y
Therefore
(10+y)*y=1200
y^2+10*y-1200=0
y=-40,30
But y can't be negative
So y=30=original price of book

Answer 2

Answer:

refers to the attachment