#### Question

The total cost price of a certain number of identical articles is Rs 4800. By selling the articles at Rs 100 each, a profit equal to the cost price of 15 articles is made. Find the number of articles bought.

#### Solution

Let the number of articles bought be x.

Total cost price of x articles = Rs 4800

Cost price of one article = Rs `4800/x`

The selling price of each article = Rs 100

Selling price of x articles = Rs 100x

Given, Profit = C.P. of 15 articles

∴ 100x - 4800 = `15 xx 4800/x`

`100x^2 - 4800 = 15 xx 4800`

`x^2 - 48x - 720 = 0`

`x^2 - 60x + 12x - 720 = 0`

x(x - 60) + 12(x - 60) = 0

(x - 60)(x + 12) = 0

x = 60, -12

Since number of article cannot be negative So x = 60.

Thus the number of articles bought is 60.

Is there an error in this question or solution?

Solution The Total Cost Price of a Certain Number of Identical Articles is Rs 4800. by Selling the Articles at Rs 100 Each, a Profit Equal to the Cost Price of 15 Articles is Made. Find the Concept: Quadratic Equations.