Prep Math question

gastank · 发表于 2012-1-22 01:20:34

Three boxes of supplies have an average weight of 7kg and a median weight of 9kg. What is the maximum possible weight, in kg, of the lightest box?

a. 1
b. 2
c. 3
d. 4
e. 5

Related to this, if I have 1, 2, 2, what is the median? Thanks.

ethunder · 发表于 2012-1-22 01:22:40

is 2

gastank · 发表于 2012-1-22 01:38:33

the answer is 3. I'm confused too. so what is the median if we have a series of 1, 2, 2 for example?

WhiteSuby · 发表于 2012-1-22 02:02:20

Sum=7*3=21
the median is 9 meaning A 9 B
A+B=21-9=12

You want to minimize B to maxmize A; in other words, B is at least 9. If B is at least 9, A has to be 12-9=3.

gastank · 发表于 2012-1-22 07:25:37

so, 3, 9, 9 的median is 9?

WhiteSuby · 发表于 2012-1-22 08:03:44

Yes; you should read Statistic foundation first.

Any odd set of numbers, the median is always the middle one.
Any even set of numbers, the median is always the sum of the middle two divided by 2.

gastank · 发表于 2012-1-22 22:40:56

多谢。这样这道题就明白了。

la2ny · 发表于 2012-7-4 00:51:58

thank you, tricky question with well explained answer

Prep Math question

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块