Answer:
Option C
Explanation:
Let S.P = Rs. $x$. New S.P = Rs. $\frac{x}{2}$, Loss = 30%.
So, C.P = Rs. $\left(\frac{100}{70}\times\frac{x}{2}\right)$
$=$ Rs. $\frac{5x}{7}$.
Profit = Rs. $\left(x-\frac{5x}{7}\right)$ = Rs. $\frac{2x}{7}$
$\therefore$ Profit% $=\left(\frac{2x}{7}\times\frac{7}{5x}\times 100\right)$%
$=40$%