Kindly answer the question.

Solution
Let the total number of articles bought by the trader = x.

Cost price of x article = Rs. 1200

∴Cost price of 1 article  = Rs. $\frac{1200}{x}$

As 10 articles were damaged, then the number of articles sold by the trader = (x – 10)

Selling price of (x - 10) articles = 1200 + 60 = Rs. 1260

Selling price of each articles = $\frac{1260}{x-10}$

Given: 

$$\begin{gathered} \frac{1260}{x-10}-\frac{1200}{x}=2 \\ \frac{1260x-1200x+12000}{x(x-10)}=2 \\ \frac{60x+12000}{x^2-10x}=2 \\ 60x+12000=2x^2-20x \end{gathered}$$
2x² - 20x - 60x - 12000 = 0
2x² - 80x - 12000 = 0
x² - 40x - 6000 = 0
x² - 100x + 60x - 6000 = 0
x(x - 100) + 60(x - 100) = 0
(x + 60)(x - 100) = 0
x = - 60, x = 100
Neglect negative term, as number of articles cannot be negative, so, we have, 
x = 100
​​​​Therefore, the total number of articles bought by the trader =  100