sandy buys an old scooter for $ 900 and spends $ 300 on its repairs . if sandy sells the scooter for $ 1320 , what is the gain percent ?
"selling price / total cost = 1320 / 1200 = 1.1 the gain percent is 10 % . the answer is e ."
multiply(divide(subtract(1320, add(300, 900)), add(300, 900)), const_100)