lordw wrote:

Last month 15 homes were sold in Town x. The average sale price of the homes was $150,000, and the median price was $130,000. WHich of the following statements must be true?

I. at least one of the homes was sold for more than $165,000

II. at least one of the homes was sold for more than $130,000 and less than $150,000

III. At least one of the homes was sold for less than $130,000

I know that the median is the 8th number.

To answer to statement I.

I imagine 7 numbers for 130k each and 7 numbers for 165k each plus the middle one gives less than the total, so I. is true and III. is false.

But can not imagine how to make a good shortcut to know whether II is false. Tks guys for your help

assume they are in ascending order.

x1 x2 x3 x4 x5 x6 x7 130k x9 x10 x11 x12 x13 x14 x15

For I we need to find the least value of x9

this is possible when x1=...=x7=130k

and x9=x10..=x15 = y

8*130+ y*7=15*150

y= 1210/7 ~ 171.5K

so minimum value of x9 must be 171.5k which is > 165k

this case automatically elimantes II and III.

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