You have a coupon for 10% off the sale price of a surfboard. which is the better buy? explain your reasoning. ? 40% off the regular price ? 30% off the regular price and then 10% off the sale price 40% of $150 = $ , so the sale price is $ . 30% of $150 = $ , so the sale price is $ . 10% of that sale price is $ , so after using the coupon, the sale price is $ .