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A is a set of numbers whose average (arithmetic mean) is 15

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A is a set of numbers whose average (arithmetic mean) is 15 [#permalink] New post   03 Nov 2020, 11:34
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A is a set of numbers whose average (arithmetic mean) is 15. B is a set that is generated by multiplying each number in A by six.


Quantity A
Quantity B
The arithmetic mean of the numbers in set B
90


A) Quantity A is greater.
B) Quantity B is greater.
C) The two quantities are equal.
D) The relationship cannot be determined from the information given.

Source: 320 GRE Math Questions
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C
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Re: A is a set of numbers whose average (arithmetic mean) is 15 [#permalink] New post   18 Nov 2020, 08:23
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A can assume many forms for eg. A = {15,15} or {0,15,30} or {10,15,20} or { 5,10,15,20,25}. In all cases avg is 15.
Now, B can be reworded as 6*(avg of A). Since avg of A is always 15 B will always be 90
Hence C
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Re: A is a set of numbers whose average (arithmetic mean) is 15 [#permalink] New post   05 Aug 2022, 23:35
Theory

    ➡ If all the numbers in the set are multiplied/divided by the same number(k) then the mean also gets multiplied/divided by the same number(k)
    ➡ New Mean = k* (Old Mean)

A is a set of numbers whose average (arithmetic mean) is 15. B is a set that is generated by multiplying each number in A by six

Average of set B = Average of Set A * 6 = 90

Clearly, Quantity A = Quantity B = 90

So, Answer will be C.
Hope it helps!

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Re: A is a set of numbers whose average (arithmetic mean) is 15 [#permalink]
05 Aug 2022, 23:35
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