DS_57想不通

plmnpler

57. 

During a sale, for each shirt that Mark purchased at the regular price, he also purchased a shirt at half the regular price.  How many shirts did Mark purchase during the sale?

(1)  The regular price of each of the shirts that Mark purchased during the sale was $21.50.

(2)  The total of the prices for all the shirts that Mark purchased during the sale was $129.00.

答案: C

21.5/2=10.75

(129-10.75)/21.5=5.5

算出来有小数肯定不对阿

zhangxirui87

21.5x+1/21.5x=129  21.5x+10.75x=129   32.25x=129   x=4

xincanyouji

为什么要用(129-10.75)/21.5?从题目中可知平价和半价的货的数量是相同的，10.75x+21.5x=129

littlestoner

for each shirt that Mark purchased at the regular price, he also purchased a shirt at half the regular price

他每用普通价格买一件衣服 , 就會用半价再买一件衣服!

就很像我们現在的衣服市場阿...

买二件 , 第二件半价!

plmnpler

汗，题又没看明白，懂了，谢谢以上！