Question

求解简单的GMAT数学，要过程，感谢

1.If the average (arithmetic mean) of 3, 8, and w is greater than or equal to 7 and less than or equal to 44, what is the greatest possible value of w ?

A. 11
B. 21
C. 55
D. 121
E. 132
Answer:

2.Can a certain rectangular sheet of glass be positioned on a rectangular tabletop so that it covers the entire tabletop and its edges are parallel to the edges of the tabletop?
(1) The tabletop is 36 inches wide by 60 inches long.
(2) The area of one side of the sheet of glass is 2,400 square inches.

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.
Answer:

3.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.
Answer:
这题啥意思？

4.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.
Answer:

Answer 1

我翻译一下吧，你看了应该就会做了。
1、如果3，8和w的算术平均值大于或等于7，而且小于或等于44，那么w的最大可能值是多少？
44*3 - 3 - 8 = 121

2、一个矩形的玻璃板是否能够完全覆盖一个矩形的桌面，而且玻璃板的边和桌面的边是平行的？
(1)桌面36英寸宽，60英寸长。
(2)玻璃板面积是2400平方英寸。
选E，两个条件相加也不充分。比如玻璃板是20*120。

3、n是一个两位的正整数，如果组成n的这两个数字（比如n是14，则这两个数字是1和4）的乘积是2，n是多少？
(1) n 是奇数
(2) n 比20大.
选D，两个都单独充分。因为乘积是2，所以n不是12就是21。(1)单独即可保证n只能是21，(2)单独即可保证n是21。

4、有n个学生，m个教室。如果 3<m<13<n，能否可能把每个学生都安排到其中一间教室，以保证每间教室的人数都相同？
(1)把3n个学生平均安排到m间教室是可能的。
(2)把13n个学生平均安排到m间教室是可能的。
其实这道题就是问：
(1)如果3n/m 是整数，那么n/m是整数。
(2)如果13n/m是整数，那么n/m是整数。
(1)肯定不充分，n=21，m=9
(2)充分。因为m小于13，而且13是质数，所以13一定和m是互质的，所以如果13n能够被m整除，那么n一定能被m整除。
选B。

Answer 2

1.m____3n m can’t be 3, it’s possible that n is divisible by m,
or a factor *3=m(eg m=6 n=2*4)
2.m____13n,m is less than 13, so there is no way m=(a factor of n )*13