gita bought a book at a price of ₹720 and sold it at a pricwhich is five fourths of its cost price . find the profit percent
Answers
Let X= cost of a book, Y= number of books you buy.
Then XY=$720 (given).
If cost of books is reduced by $5 (then cost is X-5), you could buy 2 more books (Y+2 books) for same price
So (X-5)(Y+2) = 720
From first equation: Y=720/X
Then Y+2 = 720/X+2 = (720+2X)/X
and (X-5)(720+2X)/X=720
(X-5)(720+2X) = 720X
720X + 2X^2 - 5*720 -10X = 720X
2X^2 - 10X - 3600 = 0
X^2 - 5X - 1800 = 0
This factors to: (X-45)(X+40) = 0
and has solutions X=-40 and X=45. X=-40 does not makes sense since the price cannot be negative, so the original price of the books is $45.
Y = number of books = 720/45 = 16 books
Answer:
The profit percent is 30 %
Step-by-step explanation:
Given,
Cost of book = 720 rs.
:- Selling cost = 720×5/4
= 940 rs.
Gain = 940-720 rs.
= 220 rs.
:- Gain % = 940/720×100
= 30%