on a purchase of $ 110 , a store offered a payment plan consisting of a $ 10 down payment and 12 monthly payments of $ 10 each . what percent of the purchase price , to the nearest tenth of a percent , did the customer pay in interest by using this plan ?
"12 * 10 + 10 = 130 ( 10 / 110 ) * 100 = 9.1 answer : d"
multiply(divide(subtract(add(multiply(10, 12), 10), multiply(10, 12)), 110), const_100)