明天就要一战GMAT了，刚刚做了一次模拟，真的很沮丧，只有610，比报名时候完全没
准备的第一次模拟还要低...唉，不知道这一整个寒假的准备会不会有成果.而且更心酸
的是数学错了好多...不知道是不是脑子坏掉，现在都没什么自信了...
烦请大家帮忙解释下这几题，实在不太会...谢谢
1.If n is a positive integer and the product of all the integers from 1 to n,
inclusive, in a multiple of 990, what is the least possible value of n?
a. 10
b. 11
c. 12
d. 13
e. 14
2.
7.51 8.22 7.86 8.36 8.09 7.83
8.30 8.01 7.73 8.25 7.96 8.53
A vending machine is designed to dispense 8 ounces of coffee into a cup. After
a test that recorded the number of ounces of coffee in each of 1000 cups dispensed
by the vending machine, the 12 listed amounts, in ounces, were selected from
the data. If the 1000 recorded amounts have a mean of 8.1 ounces and a std dev
of 0.3 ounce, how many of the 12 listed amounts are within 1.5 std dev of the mean?
a. 4
b. 6
c. 9
d. 10
e. 11
3. For a certain race, 3 teams were allowed to enter 3 members each. A team earned
6-n points whenever one of its members finished in nth place, where 1<=n<=5.
There were no ties, disqualifications, or withdrawals. If no team earned more than
6 points, what is the least possible score a team could have earned?
a. 0
b. 1
c. 2
d. 3
e. 4
1﹣3答案分别是
b.11
e.11
d.3
不是很理解，想请教下为什么？
先谢谢：）