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The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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28 Dec 2017, 00:25
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Re: The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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28 Dec 2017, 04:13
Bunuel wrote: The average of a, b, and c is 8, and the average of a and b is 10. If the average of a and c is 6, what is the value of a – c ?
A. 8 B. 7 C. 6 D. 5 E. 4 We'll start by writing by writing all our information as equations and then simplify them. This is a Precise approach. (a+b+c)/3 = 8 > a+b+c=24 (a+b)/2 = 10 > a+b=20 (a+c)/2 = 6 > a+c=12 We'll subtract the first two equations to get c = 4 and substitute c=4 into our third equation to get a = 8 then a  c = 4 (E) is our answer.
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The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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28 Dec 2017, 05:36
Bunuel wrote: The average of a, b, and c is 8, and the average of a and b is 10. If the average of a and c is 6, what is the value of a – c ?
A. 8 B. 7 C. 6 D. 5 E. 4 Substituting twice. \(\frac{a + b + c}{3} = 8\) \(a + b + c = 24\) \(\frac{a + b}{2} = 10\) \(a + b = 20\) \(20 + c = 24\) \(c = 4\) \(\frac{a + c}{2} = 6\) \(a + c = 12\) \(c = 4\) \(a = 8\) \((a  c) = (8  4) = 4\) Answer E
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Re: The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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28 Dec 2017, 05:54
a+b+c/3 =8 ==> a+b+c= 24 add a+b/2 and a+c/2 => 2a+b+c= 32=> a+24=32=>a= 8 8+c/2=6=>c=4 ac=4



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Re: The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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02 Feb 2018, 05:26
The correct option is E (Just tests your knowledge of averages) . This is a fairly easy question. What could the level of this question be? It looks like something lesser than a 500.



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Re: The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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02 Feb 2018, 05:30
ManasviHP wrote: The correct option is E (Just tests your knowledge of averages) . This is a fairly easy question. What could the level of this question be? It looks like something lesser than a 500. May be you will get this question if you flunk tougher questions continuously. Posted from my mobile device
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Re: The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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02 Feb 2018, 07:23
Bunuel wrote: The average of a, b, and c is 8, and the average of a and b is 10. If the average of a and c is 6, what is the value of a – c ?
A. 8 B. 7 C. 6 D. 5 E. 4 \(a + b + c = 24\)> (I) \(a + b = 20\)>(II) \(a + c = 12\)>(III) From (I) and (II) we get \(c = 4\) From (II) and (III) we get \(b = 12\) Hence \(a = 8\) Thus, \(a  c = 8  4\) Answer will be (E) 4
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Re: The average of a, b, and c is 8, and the average of a and b is 10. If [#permalink]
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05 Feb 2018, 10:18
Bunuel wrote: The average of a, b, and c is 8, and the average of a and b is 10. If the average of a and c is 6, what is the value of a – c ?
A. 8 B. 7 C. 6 D. 5 E. 4 We can create the equations: (a + b + c)/3 = 8 a + b + c = 24 and (a + b)/2 = 10 a + b = 20 and (a +c)/2 = 6 a + c = 12 Substituting, we obtain: 20 + c = 24 c = 4 Thus, a + 4 = 12, so a = 8. Finally, we have a  c = 8  4 = 4. Answer: E
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Re: The average of a, b, and c is 8, and the average of a and b is 10. If
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