A trader sold an article at a gain of 20%. Had he purchased it for 40% more and sold for Rs 24 less, then he would have incurred a loss of 20%. What is the cost price (in Rs) of the article?

Let cost price of article = Rs. $$100x$$

Profit % = 20%

=> Selling price = $$100x+(\frac{20}{100}\times100x)$$

= $$100x+20x=Rs.$$ $$120x$$

Now, new cost price = $$100x+(\frac{40}{100}\times100x)$$

= $$100x+40x=Rs.$$ $$140x$$

Also, new selling price = Rs. $$(120x-24)$$

=> Loss % = $$\frac{140x-(120x-24)}{140x}\times100=20$$

=> $$\frac{20x+24}{7x}=\frac{20}{5}$$

=> $$20x+24=4\times7x$$

=> $$28x-20x=24$$

=> $$x=\frac{24}{8}=3$$

$$\therefore$$ Cost price = $$100\times3=Rs.$$ $$300$$

=> Ans - (B)