有几道数学题想请教下大家~~

xyxyxy_123

1.For any integer n greater than 1, n
denotes the product of all the integers
from 1 to n, inclusive. How many
prime numbers are there between
6 + 2 and 6 + 6, inclusive?
(A) None
(B) One
(C) Two
(D) Three
(E) Four  这道为什么选的是a？
2. If an integer n is divisible by both 6 and
8, then it must also be divisible by
which of the following?
(A) 10
(B) 12
(C) 14
(D) 16
(E) 18  这道16为什么不可以？答案是12
3. Of the science books in a certain
supply room, 50 are on botany, 65 are
on zoology, 90 are on physics. 50 are
on geology, and 110 are on chemistry.
If science books are removed
randomly from the supply room, how
many must be removed to ensure that
80 of the books removed are on the
same science?
(A) 81
(B) 159
(C) 166
(D) 285
(E) 324 这道能给详细的解题步骤嘛？ 答案是E
4.A certain shade of gray paint is
obtained by mixing 3 parts of white
paint with 5 parts of black paint. If 2
gallons of the mixture is needed and
the individual colors can be purchased
only in one-gallon or half- gallon cans,
what is the least amount of paint, in
gallons, that must be purchased in
order to measure out the portions
needed for the mixture?
(A) 2
(B)2又1/2
(C) 3
(D)3又1/2
(E) 4  这道答案是B还是E啊？

xyxyxy_123

xyxyxy_123

没有人做到这个的吗？

xyxyxy_123

没有人回啊

xyxyxy_123

还有 这道题为什么选A？ NN们能给出详细解释嘛？  谢谢啦~~~

xyxyxy_123

If the sum of 7 consecutive integers is
434, then the greatest of the 7 integers
is
(A) 71
(B) 69
(C) 67
(D) 65
(E) 62  这题难道不是选65，为什么答案是71？

xyxyxy_123

xyxyxy_123

xyxyxy_123

ztc199201290411 发表于 2016-3-20 23:17
42套gmat数学是什么啊 求分享 一下

就是这个

xyxyxy_123

就是这个  答案有的不全