查了一下，这题没人问好象
A pharmaceutical company received $3 million in royalties on the first $20 million in sales of the generic equivalent of one of its products and then $9 million in royalties in next $108 million in sales. By approximately what percent did the ratio of royalties to sales decrease from the first $2o million in sales to the next $108 million in sales?
这题是什么意思？我看不懂 我的想法是：3/20-9/108 但是找不到答案 答案是45% | 
