Original price of 1 mango =x Rs (let)
$\therefore$ C.P. of 1 mango=$\frac{100x}{125}$
$=\frac{4x}{5} $Rs.
Case II, According to question,
$x+1=\frac{4x}{5}\times \frac{150}{100}$
$\Rightarrow x+1= \frac{6x}{5} \Rightarrow \frac{6x}{5}-x=1$
$\Rightarrow \frac{x}{5}=1 \Rightarrow x=5$ Rs.