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The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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01 Oct 2012, 05:05
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The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and (A) 15 (B) 25 (C) 35 (D) 45 (E) 55 Practice Questions Question: 53 Page: 159 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you!
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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01 Oct 2012, 05:05
SOLUTIONThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and(A) 15 (B) 25 (C) 35 (D) 45 (E) 55 The average of 10, 30, and 50 is \(\frac{10+30+50}{3}=30\). The average of 20, 40 and x must be 305=25, so the sum of these 3 numbers must be 3*25=75 > 20+40+x=75 > x=15. Answer: A.
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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01 Oct 2012, 05:29
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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The average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and (A) 15 (B) 25 (C) 35 (D) 45 (E) 55 Average of 10,30,50 = 30 Average of 20,40 & x = 25 so 60 + x = 75> x = 15 Answer A
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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04 Oct 2012, 00:47
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Answer is A (15)
Since 10, 30 and 50 are numbers in equally spaced sets, average is 30
Now 30 is 5 greater than 25 ....Thus average of 20, 40 and (x) is 25 ......This implies, sum of 3 numbers should be 75 to make the average = 25
Thus, answer is 15 = 75  20  40



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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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04 Oct 2012, 14:05
SOLUTIONThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and(A) 15 (B) 25 (C) 35 (D) 45 (E) 55 The average of 10, 30, and 50 is \(\frac{10+30+50}{3}=30\). The average of 20, 40 and x must be 305=25, so the sum of these 3 numbers must be 3*25=75 > 20+40+x=75 > x=15. Answer: A. Kudos points given to everyone with correct solution. Let me know if I missed someone.
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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10 Sep 2014, 19:08
Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and (A) 15 (B) 25 (C) 35 (D) 45 (E) 55 Practice Questions Question: 53 Page: 159 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you! 10+30+50 = 90 90/3=30. so mean of 20+40+x should be 25... 25*3=75(total), 60+x=75 x=15.



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The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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10 Sep 2014, 22:54
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Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and (A) 15 (B) 25 (C) 35 (D) 45 (E) 55 Algebraic Method (Forming single equation for result) \(\frac{10 + 30 + 50}{3} = \frac{20 + 40 + x}{3} + 5\) x = 15 Shortcut (By observation) Method10, 30, 50 are equally spaced; so average = 30 For the other set, required average would be 30  5 = 25 It means total = 75 Required number = 75  (20+40) = 15
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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01 Oct 2015, 21:29
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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30 May 2016, 05:24
Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and (A) 15 (B) 25 (C) 35 (D) 45 (E) 55 Let’s first determine the average of 10, 30, and 50, using the average formula. average = sum/quantity average = (10+30+50)/3 average = 90/3 average = 30 We can now rephrase the question to ask: "30 is 5 more than the average of 20, 40, and what value?" Let’s label the missing value as n and create an equation. 30 = (20+40+n)/3 + 5 25 = (20+40+n)/3 75 = 60 + n 15 = n The answer is A.
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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30 May 2016, 06:15
[quote="Bunuel"] The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and (A) 15 (B) 25 (C) 35 (D) 45 (E) 55 /quote] avg of (10, 30, 50) = (10+30+50)/ 3 = 30. Avg of next set = 25. There are 3 nos. So sum of those 3 nos. = 25 * 3 = 75. Third number = 75  2040 = 15 (A) is the answer.



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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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17 Dec 2016, 17:30
Here is my solution to this one =>
Mean(1) = 30 (Notice that it is an AP series so the median will be the mean)
Mean(2)=\(\frac{60+x}{3}\)
As per question \(30=\frac{60+x}{3} +5\) Hence x=15 Hence A
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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28 Dec 2016, 17:42
\(a1 : \frac{90}{3} = 30\) a2: \(25 = \frac{60 + x}{3}\) x = 15 A
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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01 Apr 2017, 09:48
Bunuel wrote: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectThe average (arithmetic mean) of 10, 30, and 50 is 5 more than the average of 20, 40, and (A) 15 (B) 25 (C) 35 (D) 45 (E) 55 Practice Questions Question: 53 Page: 159 Difficulty: 600 GMAT Club is introducing a new project: The Official Guide for GMAT® Review, 13th Edition  Quantitative Questions ProjectEach week we'll be posting several questions from The Official Guide for GMAT® Review, 13th Edition and then after couple of days we'll provide Official Answer (OA) to them along with a slution. We'll be glad if you participate in development of this project: 1. Please provide your solutions to the questions; 2. Please vote for the best solutions by pressing Kudos button; 3. Please vote for the questions themselves by pressing Kudos button; 4. Please share your views on difficulty level of the questions, so that we have most precise evaluation. Thank you! (10+30+50)/3  (20+40+x)/3= 5 30(60+x)/3=5 x=9075=15




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