By selling 10 articles, a man gains equal to cost price of 2 articles, the profit made is :

1. 40%

2. 20%

3. 25%

4. 50%

Let the C.P. of 1 article be ₹ 100.

So, the C.P. of 2 article = ₹ 100 x 2 = ₹ 200

Similarly, the C.P. of 10 article = ₹ 100 x 10 = ₹ 1000

Gain = Cost price of 2 articles = ₹ 200

As we know,

$\text{Profit\%} = \dfrac{\text{Profit}}{\text{C.P.}} \times 100\%\\[1em] = \dfrac{200}{1000} \times 100\%\\[1em] = \dfrac{1}{5} \times 100\%\\[1em] = \dfrac{100}{5}\%\\[1em] = 20\%$

Hence,option 2 is the correct option.