作者kim0330 (无)
看板GMAT
标题[计量] pp上的DS
时间Fri Nov 27 01:05:50 2009
1.During an experiment,some water was removed from each of 6 water tanks.If
the standard deviation of the volumes of water in the tanks at the beginning of
the experiment was 10 gallons,what was the standard deviation of the
volumes of water in the tanks at the end of the experiment?
(1)For each tank,30 percent of the volume of water was in the tank at the
beginning of the experiment was removed during the experiment.
(2)The average (arithemetic mean) volume of water in the tanks at the end
of the experiment was 63 gallons.
答案是A 其实我不是很懂题目的意思~~但应该是利用S.D概念吧......
2.If p is a prime number greater than 2,what is the value of p?
(1)There are a total of 100 prime numbers between 1 and p+1.
(2)There are a total of p prime numbers between i and 3912.
答案是D
谢谢 谢谢 谢谢
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1F：推 Chest:第一题，因为所有的tank都减少30%且原始volume相同，故标准 11/27 08:20
2F：→ Chest:差不变，仍然是10 11/27 08:20