GWD27-13 和另一道数学题 超级难 有人回复后我公布答案

Theater M has 25 rows with 27 seats in each row.  How many of the seats were occupied during a certain show?

(1)
    During the show, there was an average (arithmetic mean) of 10 unoccupied seats per row for the front 20 rows.

(2)   During the show, there was an average (arithmetic mean) of 20 unoccupied seats per row for the back 15 rows.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

另有一道PREP上的题和这题类似:

DS: 说一帮人不是MANAGER就是DIRECTOR. 问M和D 的人数比.

DS: 说一帮人不是MANAGER就是DIRECTOR. 问M和D 的人数比.

1) M的平均工资比总平均工资少5000.

1) M的平均工资比总平均工资少5000.

2) D的平均工资比总平均工资多15000.

2) D的平均工资比总平均工资多15000.

汗啊.

汗啊.

Theater M has 25 rows with 27 seats in each row.  How many of the seats were occupied during a certain show?

E  ......2个都只能算出前N排的空位数 其他排的情况不知

E  ......2个都只能算出前N排的空位数 其他排的情况不知

第一道是E. 

第二道呢?  我觉得这2道应该有接近的算法...

第二题有个前提，就是所有M工资相同以及所有D工资相同

这样的话M/D=15000/5000=3/1

有一道类似的DS题目，说有男女一共1400老师，共有42%赞成一个事情，问南女老师比例

1，男老师有36%赞成，女老师有50%赞成

2，男老师同意的有288人

答案A

第一题是A  

第二题  设总平均工资为k, 人数分别为m,d

则   m(k-5000)+d(k+15000)=k(m+d)

于是  -5000m+15000d=0

        m/d=3