if the selling price of 50 articles is equal to the cost price of 40 articles , then the loss or gain percent is ?
"let c . p . of each article be re . 1 . then , c . p . of 50 articles = rs . 50 ; s . p . of 50 articles = rs . 40 . loss % = 10 / 50 * 100 = 20 % . answer : a"
subtract(50, 40)