A dealer sold an article at 6% loss. Had he sold it for Rs. 64 more, he would have made a profit of 10%. Then the cost of the article is = ?

Answer: Option A

Let the cost price of the article = Rs. 100x
Loss% = 6%
$$\begin{array}{rl}& \text{SP}=100x\times \frac{94}{100}=\text{Rs}\text{.}94x\\ & \text{If}\text{SP}\text{is}\text{Rs}\text{.}\text{64}\text{more,}\\ & \Rightarrow \text{New}\text{SP}=\text{Rs}\text{.}\left(94x+64\right)\\ & \Rightarrow \text{Profit}\%\\ & \frac{\left(94x+64\right)-100x}{100x}\times 100=10\\ & \Rightarrow 64-6x=10x\\ & \Rightarrow 10x+6x=64\\ & \Rightarrow 16x=64\\ & \Rightarrow x=\frac{64}{16}\\ & \therefore x=4\\ & \therefore \text{Cost}\text{Price}=100\times 4\\ & =\text{Rs}\text{.}400\end{array}$$