SOS数学难题

1.A department manager distributed a number of pens, pencils, and pads among the staff in the department, with each staff member receiving x pens, y pencils, and z pads. How many staff members were in the department ?
(1) The numbers of pens, pencils, and pads that each staff member received were in the ratio 2 : 3 : 4, respectively.
(2) The manager distributed a total of 18 pens, 27 pencils, and 36 pads.

这个题目我觉得根据配比关系只能是9人啊，答案是E

2.A school administrator will assign each student in a group of n students to one of m classrooms. If 3 < m < 13 < n, is it possible to assign each of the n students to one of the m classrooms so that each classroom has the same number of students assigned to it?
(1) It is possible to assign each of 3n students to one of m classrooms so that each classroom has the same number of students assigned to it.
(2) It is possible to assign each of 13n students to one of m classrooms so that each classroom has the same number of students assigned to it

3.For what percent of those tested for a certain infection was the test accurate; that is, positive for those who had the infection and negative for those who did not have the infection?
(1) Of those who tested positive for the infection, 81 did not have the infection.

(2) Of those tested for the infection, 90 percent tested negative.

看不太懂呢

1/如果staff只有一个人，那么可以

  如果三个人呢，也是可以的，只要分配按照  6 pens  9pencile  12 pads就可以了

2、其实题目问 n是不是可以背m整除。呵呵

答案是不是b嗄

3、是不是e嗄。

3、