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The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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24 Nov 2014, 06:35
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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24 Nov 2014, 06:59
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If the average of four numbers is 4x + 3, then the sum of all four numbers if 4 * (4x + 3) = 16x + 12. If one of the numbers is x, then the average of the remaining three numbers would be: (16x + 12  x)/3 = (15x + 12)/3 = 5x + 4.
Answer is D.



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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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24 Nov 2014, 07:39
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Bunuel wrote: Tough and Tricky questions: Number Properties. The average (arithmetic mean) of four numbers is 4x + 3. If one of the numbers is x, what is the average of the other three numbers? A) x + 1 B) 3x + 3 C) 5x + 1 D) 5x + 4 E) 15x + 12 Kudos for a correct solution.Sum of all the four numbers = (4x+3)*4> 16x+12 one of the number is x so the sum of the other three numbers will be 16x+12x> 15x+12 average = sum/3> (15x+12)/3 = 5x+4. D
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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24 Nov 2014, 08:37
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The answer is D. Sum of 4 number is 16x+12 Sum of 3 no except x is 15x+12 => mean is 5x+4



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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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24 Nov 2014, 09:21
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Sum of 4 no is 16x+12 Sum of 3 no except x is 15x+12 => mean is 5x+4 The answer is D.



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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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24 Nov 2014, 10:21
\(Average = \frac{(Sum of Items)}{(Number of Items)}\)
One of the number is \(X\) Let us say other numbers are \(A\),\(B\),\(C\)
\(Average\) \(=\) \(\frac{(X+A+B+C)}{4}\) = \(4X+3\) \(A+B+C= 4(4X+3) X = 15X+12\)
\(Average\) of three numbers(A,B,C) is = \(\frac{(A+B+C)}{3}\) \(=\) \(\frac{(15X+12)}{3}\) \(=\) = \(5X+4\)
Answer: D



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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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24 Nov 2014, 19:34
Answer = D) 5x + 4Say x = 1, so average = 7 & total = 28 [For 4 numbers] Total of remaining 3 numbers = 281 = 27 Average\(= \frac{27}{3} = 9\) Only option D fits in = 5*1 + 4 = 9
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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25 Nov 2014, 04:50
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Sum of all the four numbers = (4x+3)*4 => 16x+12 one of the number is x so the sum of the other three numbers will be 16x+12x =>15x+12 average = sum/3 => (15x+12)/3 => 5x+4 Answer D
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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25 Nov 2014, 05:02
Given that , Sum of three no +x=4(4x+3) Sum of three no = 15x+12
Mean of the three =5x+4
Answer D



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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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05 Dec 2016, 08:49
(A+b+c+ x) / 4 = 4x+3 A+b+c+x = 16x+12 A+b+c = 15x+12. This is the sum.
To find the average: (15x + 12) / 3 = 5x+4
Answer: D



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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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05 Dec 2016, 09:07
sum of 4 numbers/4 = 4x+3 x+sum of three numbers/4 = 4x+3 Sum of three numbers = 4(4x+3) x = 15x+12 Average of three numbers = Sum of three numbers/3 = 5x+4 Answer (D)
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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05 Dec 2016, 09:18
Bunuel wrote: Tough and Tricky questions: Number Properties. The average (arithmetic mean) of four numbers is 4x + 3. If one of the numbers is x, what is the average of the other three numbers? A) x + 1 B) 3x + 3 C) 5x + 1 D) 5x + 4 E) 15x + 12 \(\frac{4( 4x + 3 )  x}{3}\) \(= \frac{16x + 12  x}{3}\) \(= \frac{15x + 12}{3}\) \(= 5x + 4\) Hence, answer will be (D) 5x + 4
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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10 Dec 2016, 05:22
Here is my solution to this one >
Sum (4)=mean*4 => \(16x+12\) Hence sum(3) => \(16x+12x => 15x+12\) New Mean = \(\frac{15x+12}{3}=> 5x+4\)
Hence D
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The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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01 Feb 2017, 23:10
This question has to do with number properties A generic formula can be applied to multiple instances of the same questions. In general multiply one of the given formula by the amount of numbers N(5x + 8) for example. > 25X + 8  x = 24x  x = 24/4 + 2 > Solution



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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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02 Feb 2017, 07:57
Bunuel wrote: Tough and Tricky questions: Number Properties. The average (arithmetic mean) of four numbers is 4x + 3. If one of the numbers is x, what is the average of the other three numbers? A) x + 1 B) 3x + 3 C) 5x + 1 D) 5x + 4 E) 15x + 12 Kudos for a correct solution.Source: Chili Hot GMAT Sum of the 4 numbers is 16x + 12 One of the number is x So, sum of the other 3 numbers is 15x + 12 Hence, average of the 3 numbers will be \(\frac{( 15x + 12 )}{3} => 5x + 4\) Thus, answer will be (D)
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Re: The average (arithmetic mean) of four numbers is 4x + 3. If one of the [#permalink]
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08 Feb 2017, 10:23
Bunuel wrote: Tough and Tricky questions: Number Properties. The average (arithmetic mean) of four numbers is 4x + 3. If one of the numbers is x, what is the average of the other three numbers? A) x + 1 B) 3x + 3 C) 5x + 1 D) 5x + 4 E) 15x + 12 We are given that the mean of four numbers is 4x + 3 and that one of the numbers is x. Thus, the sum of of the 4 numbers is 4(4x + 3) = 16x + 12. Since one of those numbers is x, the sum of the other 3 numbers is: 16x + 12  x = 15x + 12 Finally, the average of the other 3 numbers is (15x + 12)/3 = 15x/3 + 12/3 = 5x + 4. Answer: D
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