Ratio of cost price to selling price of an article is 5 : 6. If 20% discount is offered on marked price of article then marked price is what percent more than cost price?

Let M.P. = x

And cost price and selling price be 5y and 6y

So,

80%????=6????

$x = frac{{30y}}{4} Rightarrow x = 7.5y$

Required percentage = $frac{{7.5y - 5y}}{{5y}} imes 100$

$= frac{{2.5y}}{{5y}} imes 100 = 50{ m{\% }}$