Madhya Pradesh Police Exam Model Paper 3

Let CP and SP of one article be Rs. x and y respectively.
According to the question, selling price of 50 articles = the cost price of 60 articles
$\therefore 50\mathit{y}=60\mathit{x}$
$\Rightarrow \mathit{y}=6/5\mathit{x}$
Since SP for 1 article is more than CP, therefore it is gain
Gain% = {(SP - CP)/CP} × 100
$=\frac{\frac{6}{5}\mathit{x}-\mathit{x}}{\mathit{x}}\times 100$
$=\frac{\frac{1}{5}\mathit{x}}{\mathit{x}}\times 100=20\%$