脑残了 - GWD 数学不理解。。。

sarahfuzq

脑残了， 数学也不会。。。
data sufficiency

1  If the average (arithmetic mean）of the assessed values of x houses is 212,000 and the average of the assessed values of y other houses is 194000, what is the average of the assessed values of x+y houses?

1) x+y=36
2) x=2y

答案是C, 我觉得B就行， 不解中。。。


2  Last year in a group of 30 businesses, 21 reported a net profit and 15 had investments in foreign markets.  How many of the businesses did not report a net profit nor invest in foreign markets last year?

1) last year 12 of the 30 businesses reported a net profit and had investments in foreign markets
2) last year 24 of the 30 businesses reported a net profit or invested in foreign markets, or both.

答案是B, 我觉得是D,   不解中。。。。

求大牛指教。。。

qianertongre

昨天刚做这套题，选的和你一样，你得相信你随手拿到的gwd答案是可以错误的。。。如果还是觉得不爽，可以将此题复制到google上，你会看到你想要的解释的