Question

The total cost price of a certain number of identical aricles is Rs.4,800. 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.

Answer 1

Let the number of articles bought be x.
Total cost price of x articles = Rs 4800
Cost price of one article = Rs$\frac{4800}{x}$
Selling price of each article = Rs 100
Selling price of x articles = Rs 100x
Given, Profit = C.P. of 15 articles
∴ 100x – 4800 = 15 ×$\frac{4800}{x}$
100x2 – 4800x = 15 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 articles cannot be negative. So, x = 60.
Thus, the number of articles bought is 60.