Median of Q consecutive integers

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Median of Q consecutive integers

by gander123 » Thu Oct 04, 2012 1:46 pm
Hi everyone,

I recently reviewed the following question but still haven't quite understood the answer explanation:

"If Q is an odd number and the median of Q consecutive integers is 120, what is the largest of these integers?"

A: Q-1/2 +120
B: Q/2 + 119
C: Q2 + 120
D: Q+119/2
E: Q+120/2

Answer Explanation:

For an odd number of data values, the median is the middle number. Thus, 120 is the middle number, and so half of the Q-1 remaining values are at most 120 and the other half of the Q-1 remaining values are at least 120. In particular, Q-1/2 data values lie to the right of 120 when data values are listed in increasing order from left to right, and so the largest data value is 120+Q-1/2 (Answer A).

My question:

I fully understand, that Q-1/2 values of the remaining Q-1 values lie to the right of 120. However, Q could be 7 (Values)and thus, 3 values would lie to the right of 120. Since we do not know these values, these could be 290, 345, 900 or whatsoever... In this case then, 900 would be the largest of the 7 integers. BUT, the correct answer (A) would give me a value such as 7-1/2 +120 = 120 +6 = 126.

Can anyone out there help me out on this one?

I'd appreciate your help.

Kind regards,

Tobi
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by Jim@StratusPrep » Thu Oct 04, 2012 2:10 pm
You are doing your math wrong :

(7-1)/2 + 120 = 6/2 +120 = 123
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by gmat6087 » Fri Oct 05, 2012 7:51 am
gander123 wrote:Hi everyone,

I recently reviewed the following question but still haven't quite understood the answer explanation:

"If Q is an odd number and the median of Q consecutive integers is 120, what is the largest of these integers?"

A: Q-1/2 +120
B: Q/2 + 119
C: Q2 + 120
D: Q+119/2
E: Q+120/2

Answer Explanation:

For an odd number of data values, the median is the middle number. Thus, 120 is the middle number, and so half of the Q-1 remaining values are at most 120 and the other half of the Q-1 remaining values are at least 120. In particular, Q-1/2 data values lie to the right of 120 when data values are listed in increasing order from left to right, and so the largest data value is 120+Q-1/2 (Answer A).

My question:

I fully understand, that Q-1/2 values of the remaining Q-1 values lie to the right of 120. However, Q could be 7 (Values)and thus, 3 values would lie to the right of 120. Since we do not know these values, these could be 290, 345, 900 or whatsoever... In this case then, 900 would be the largest of the 7 integers. BUT, the correct answer (A) would give me a value such as 7-1/2 +120 = 120 +6 = 126.

Can anyone out there help me out on this one?

I'd appreciate your help.

Kind regards,

Tobi
Hey Tobi,

You missed a point in the question Q consecutive integers. So the values 290, 345, 900 or whatsoever will never appear.

lets take Q=5 or any other odd number.

so numbers will be
118, 119, 120, 121, 122
Now put the values to the options only Option A satisfies this condition for any odd number

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by gander123 » Mon Oct 08, 2012 12:45 pm
Hey guys,

Thanks for your answers. I got that subtraction wrong because I was in a hassle ;).

However, Gmat6087 I really like your answer.. I did not know that the word "consecutive" means only integers that have a difference of "1". I realize I really have to pay attention to the wording. It's a bit of a language barrier also ... from German to English.

But thanks indeed, I liked both your answers !

Regards!