If the average (arithmetic mean) of five consecutive negative integers is 2k - 1, what is the difference between the greatest and least of the five integers?
A. 4
B. 4k
C. 4k + 4
D. 4 - 4k
E. 4k^2 − 4k
OA A
Source: Magoosh
If the average (arithmetic mean) of five consecutive negativ
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- fskilnik@GMATH
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We have a finite arithmetic sequence, hence the average of the 5 integers is their median, that is the third (middle) term.BTGmoderatorDC wrote:If the average (arithmetic mean) of five consecutive negative integers is 2k - 1, what is the difference between the greatest and least of the five integers?
A. 4
B. 4k
C. 4k + 4
D. 4 - 4k
E. 4k^2 − 4k
Source: Magoosh
Conclusion: the greatest is (2k-1) + 2 and the least is (2k-1) - 2 , and their difference (our FOCUS) is [(2k-1)+2]-[(2k-1)-2] = 4.
This solution follows the notations and rationale taught in the GMATH method.
Regards,
Fabio.
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The value of k is irrelevant.BTGmoderatorDC wrote:If the average (arithmetic mean) of five consecutive negative integers is 2k - 1, what is the difference between the greatest and least of the five integers?
A. 4
B. 4k
C. 4k + 4
D. 4 - 4k
E. 4k^2 − 4k
For any set of 5 consecutive integers, the difference between the greatest and least will always be 4.
The correct answer is A.
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We are asking for the range of the 5 consecutive integers. It's a fact that the range of a set of n integers is always n - 1. For example, in the set of {2, 3, 4, 5, 6, 7}, there are 6 consecutive integers, we see that the range is 7 - 2 = 5, which is 1 less than the number of consecutive integers. Therefore, in a set of 5 consecutive integers, whether they be positive or negative, the difference between the greatest and least integers, i.e., the range, is 4.BTGmoderatorDC wrote:If the average (arithmetic mean) of five consecutive negative integers is 2k - 1, what is the difference between the greatest and least of the five integers?
A. 4
B. 4k
C. 4k + 4
D. 4 - 4k
E. 4k^2 − 4k
OA A
Source: Magoosh
Answer: A
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Let x = the 1st (smallest integer)BTGmoderatorDC wrote:If the average (arithmetic mean) of five consecutive negative integers is 2k - 1, what is the difference between the greatest and least of the five integers?
A. 4
B. 4k
C. 4k + 4
D. 4 - 4k
E. 4k^2 − 4k
OA A
Source: Magoosh
So, x+1 = the 2nd integer
x+2 = the 3rd integer
x+3 = the 4th integer
x+4 = the 5th integer (greatest integer)
What is the difference between the greatest and least of the five integers?
Difference = ( x+4) - x = 4
Answer: A
Cheers,
Brent