by selling 95 pens , a trader gains the cost of 19 pens . find his gain percentage ?
"let the cp of each pen be rs . 1 . cp of 95 pens = rs . 95 profit = cost of 19 pens = rs . 19 profit % = 19 / 95 * 100 = 20 % answer : a"
multiply(divide(19, 95), const_100)