【跪求大牛】both and的含义

heyuqing1991

在亲爱的CDer提供的不知名的IR资料中有一道题表格题的选项是这样的
Exactly 50 percent of the furniture items that experienceda decrease in both total inventory and total items sold areRed mahogany.  
答案这样解释There were 6 furniture items that experienced a decrease in total inventory. Of these, 3 (exactly 50 percent) are Red mahogany. However, all19 furniture items experienced a decrease in total items sold. Only 6 ofthese (32 percent) are Red mahogany, so the statement is false.


搞不清题干中说的 items that experienced a decrease in both total inventory and total items sold 是指经历了同时两种下降的项目，还是经历了其中一种的项目哇。
有没有牛人做过这个题哇。跪求解释哇！！！