求教大神啊~~GWD数学题两道。。。

whisper15

Q5:

A department manager distributed a numberof pens, pencils, and pads among the staff in the department, with each staffmember 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.

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

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

C.BOTH statements TOGETHER are sufficient, but NEITHERstatement ALONE is sufficient.

D.EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHERare NOT sufficient.

求解为何选D啊。。。。不是要一起才能解出来吗

Q32:

If n is an integer between 10 and99, is n < 80 ?

(1)             The sum of the two digits of n is a prime number.

(2)              Each of the two digits of n is a primenumber.

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

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

C.BOTH statements TOGETHER are sufficient, but NEITHERstatement ALONE is sufficient.

D. EACH statement ALONE issufficient.

E. Statements (1) and (2) TOGETHERare NOT sufficient.

这题不是第二个条件就可以得出N无乱如何都小于80吗。。。为什么要选C呢。。。

谢谢各位大神啊！！！