4.22考试--请教数学题目--(4)

ruoancheng

Q4:

If the product of the digits of the two-digit positive integer n is 2, what is the value of n ?

(1)n is odd.

(2)n is greater than 20.



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.(D)

Q7:

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.



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.(B)

Q31:

A certain right triangle has sides of length x, y, and z, where x < y < z.  If the area of this triangular region is 1, which of the following indicates all of the possible values of y ?



A. y >

B. < y <

C. < y <

D. < y <

E. y < (A)

顷刻倾城

LZ 先把标题改了吧，跟JJ那些一样。不要出现数字啊

Q4: 这个数字只可能是12或21，所以两个条件都充分
Q7：实际上就是问你n能不能被m整除，条件1说3n可以被m整除，但是n不一定啊；条件2说13n可以被m整除，那么n肯定可以被m整除（因为n里面包含了4到12的所有因子）
最后一个不知道，看不到

ruoancheng

谢谢哦，明白了。

tangbobin

Q7还是不懂 有没有NN给个清楚点的解释。。。

Avengeryzc

第七题就是问你n是不是m的倍数，根据条件2,13n是m的倍数，m又小于13，所以n一定是m的倍数