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# The average (arithmetic mean) of six numbers is 6. If 3 is subtracted

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The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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03 Dec 2015, 06:23
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15% (low)

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77% (00:58) correct 23% (00:50) wrong based on 207 sessions

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The average (arithmetic mean) of six numbers is 6. If 3 is subtracted from each of four of the numbers, what is the new average?

A. 1.5
B. 2
C. 3
D. 4
E. 4.5

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Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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03 Dec 2015, 06:26
subtracting 3 from each is as good as subtracting 3 from avg
so 6-3 =3

or else

since am is 6
sum =36
3 subtracted from each =36-18=18
new average 18/6 =3
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Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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03 Dec 2015, 07:18
1
Sum of 6 numbers = 6*6 =36
If 3 is subtracted from each of four of the numbers , we subtract 3*4=12 from the total sum
Sum of 6 number after subtracting 3 from each of four of the numbers = 36 - 12 = 24
New average = 24/6 = 4

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Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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03 Dec 2015, 08:17
.Grr didn't read the question again
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Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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03 Dec 2015, 11:22
Bunuel wrote:
The average (arithmetic mean) of six numbers is 6. If 3 is subtracted from each of four of the numbers, what is the new average?

Let the numbers be a , b, c , d , e ,f

Quote:
average (arithmetic mean) of six numbers is 6.

So, Total of these 6 numbers must be 36

Or, a + b + c + d + e + f = 36

Quote:
3 is subtracted from each of four of the numbers

So, 12 must be subtracted from the total sum

i.e a + b + c + d + e + f - 12

Or, 36 - 12 = 24

Hence average of the 6 numbers now is 24/6 =>4

So, Answer will be (D) 4

PS : Ideally I like Skywalker18 's method and will use the said method.
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Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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10 Dec 2016, 05:54
This is a great Question.
Here is what i did in this Question=>

$$Mean =\frac{Sum}{#}$$

Hence Sum = 6*6=36
New sum => 36-(3*4) = 36-12=24
Hence New Mean = 24/6 = 4

Hence D

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Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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11 Dec 2016, 02:22
Bunuel wrote:
The average (arithmetic mean) of six numbers is 6. If 3 is subtracted from each of four of the numbers, what is the new average?

A. 1.5
B. 2
C. 3
D. 4
E. 4.5

$$a + b + c + d + e + f = 30$$

Or, $$6 + 6 + 6 + 6 + 6 + 6 = 30$$

Quote:
If 3 is subtracted from each of four of the numbers

( 6 - 3 ) + ( 6 - 3 ) + ( 6 - 3 ) + ( 6 - 3 ) + 6 + 6 = 24

So, avergae will be 24/6 = 4

Hence, answer will be (D) 4

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Thanks and Regards

Abhishek....

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Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted  [#permalink]

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09 Sep 2017, 07:47
D

sum/6=6
sum=36
36-12/6=24/6=4
Re: The average (arithmetic mean) of six numbers is 6. If 3 is subtracted   [#permalink] 09 Sep 2017, 07:47
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