作者Vinicks (信将)
看板GMAT
标题[计量]PP1-DS-Q34
时间Fri Oct 31 23:12:19 2008
34. 2927-!-item-!-187;#058&003024
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 that was
in the tank at the beginning of the experiment was removed during the
experiment.
(2) The average (arithmetic mean) volume of water in the tanks at
the end of the experiment was 63 gallons.
这题我看了一下PP1DS的详解 他写的内容好像变成这6个桶子都是一样大小的
但是我从题目中一直找不到他有写说这些桶子是一模一样的
想请问版上的大大 是我会错意呢?? 还是怎样了??
或请有大大开点一下 ^^"
THX~~~!
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1F：推 krisis:不一样大啊，不然怎麽会有SD呢~~ 11/01 04:50
2F：推 krisis:刚才看了详解，它的表示表真的像是一样大的~~ 11/01 06:54