If selling price is doubled, the profit triples. Find the profit percent

S.P be Rs. y

$3\left(y-x\right)=2\left(y-x\right)\Rightarrow y=2x$

Profit $=\text{Rs}\left(y-x\right)=\text{Rs}\text{.}\left(2x-x\right)=\text{Rs}\text{.}x$

$\therefore$ Profit $=\frac{x}{x}\times 100=100\%$