一道prep题的审题问题

阿尔的阳光

这道题疑问在审题上。。

A computer chip manufacturer expects the ratio of the number of defective chips to the total number of chips in all future shipments to equal the corresponding ratio for shipments S1, S2, S3, and S4 combined, as shown in the table above. What is the expected number of defective chips in a shipment of 60,000 chips?

A 14 B 20 C22 D24 E 25

Key:B

（expect the ratio=the corresponding ratio combined)难道不是(2/500)+(5/12000)…这样加起来的和为expect ratio吗？

但是答案是(2+5+..)/(5000+12000...)这样算法的。。。

阿尔的阳光

Airbuff 发表于 2018-7-15 18:51
the corresponding ratio for shipments S1, S2, S3, and S4 combined
题干如上，combined是修饰shipments  ...

好像看懂了。。感谢。这简直是考阅读的数学题

Airbuff

the corresponding ratio for shipments S1, S2, S3, and S4 combined
题干如上，combined是修饰shipments 不是修饰ratio，而且题干中并没有和“分别对应”有关的任何修饰词语
所以combined的是所有shipments的defective和chips，而不是分别的ratio。