manoranjan paid rupes 602• for 10 books if has to buy 3 more books how much more money will be have to pay to the bookseller
Answers
Answer:
let the shopkeeper bought x number of books for Rs.1200
price for each book = 1200/x
If he had bought 10 more books for the same amount each book would have cost Rs 20 less
it means
the cost of each books is decreased by 20 if he had bought 10 more books
I.e.
ATQ
1200/x - 1200/x + 10 = 20
1200(1/x - 1/(x+10) = 20
1/x - 1/x+10 = 20/1200
(x+10) - x /x(x+10) = 1/60
x+10 -x = x² + 10x / 60
600 = x² + 10x
x² + 10x - 600 = 0
Here quadratic equation formed ...
x² + 10x - 600 = 0
x² + 30x - 20x - 600 = 0
x(x+30) -20(x+30) = 0
(x+30) (x-20) = 0
either
(x+30) =0 or (x-20) = 0
x = -30 or x = 20
x = -30 X not possible because the number of books cant be negative
so number of books = x = 20
Answer:
18.6 rupees he pay to bookseller