Problem: if the selling price of 50 articles is equal to the cost price of 20 articles , then the loss or gain percent is :
Rationale: "c . p . of each article be re . 1 . then , c . p . of 50 articles = rs . 50 ; s . p . of 50 articles = rs . 20 . loss % = 30 / 50 * 100 = 60 % answer d"
annotated_formula: subtract(50, 20)