x sells two articles for Rs. 4000 each with no loss and no gain in the transaction. If one was sold at a gain of 25% the other is sold at a loss of = ?

Answer: Option C

Total SP = Rs. 8000 and Total CP = Rs. 8000
SP of 1^st articles = Rs. 4000
Gain on it = 25%
∴ CP of 1^st articles $$=\text{Rs}\text{.}\left(\frac{100}{125}\times 4000\right)=\text{Rs}\text{.}3200$$
∴ CP of 2^nd articles = Rs. (8000 - 3200) = Rs. 4800
SP of 2^nd articles = Rs. 4000
∴ Loss on 2^nd articles
$$\begin{array}{rl}& =\left(\frac{800}{4800}\times 100\right)\%\\ & =16\frac{2}{3}\%\end{array}$$