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Re M0828 [#permalink]
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15 Sep 2014, 23:38
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Official Solution: It's almost always better to express the average in terms of the sum: the average of four distinct positive integers is 60, means that the sum of four distinct positive integers is \(4*60=240\). Say four integers are \(a\), \(b\), \(c\) and \(d\) so that \(0 \lt a \lt b \lt c \lt d\). So, we have that \(a+b+c+d=240\). (1) The median of the three largest integers is 51 and the sum of two largest integers is 190. The mdian of \(\{b,c,d\}\) is 51 means that \(c=51\). Now, if \(b=50\), then only \(a\), will be less than 50, but if \(b \lt 50\), then both \(a\) and \(b\), will be less than 50. But we are also given that \(c+d=190\). Substitute this value in the above equation: \(a+b+190=240\), which boils down to \(a+b=50\). Now, since given that all integers are positive then both \(a\) and \(b\) must be less than 50. Sufficient. (2) The median of the four integers is 50. The median of a set with even number of terms is the average of two middle terms, so \(\text{median}=\frac{b+c}{2}=50\). Since given that \(b \lt c\) then \(b \lt 50 \lt c\), so both \(a\) and \(b\) are less than 50. Sufficient. Answer: D
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Re: M0828 [#permalink]
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07 Feb 2016, 09:17
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In statement # 2:
What about the case when both 'b' and 'c' are 50?
The problem does not state b > c anywhere.
So we can have 2 valid set of elements:
Set 1: 1, 48, 52, 139 > 2 elements are less than 50 Set 2: 1, 50, 50, 139 > 1 element is less than 50.
Insufficient > Answer must be A.



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Re: M0828 [#permalink]
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07 Feb 2016, 09:19



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Re: M0828 [#permalink]
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11 Feb 2016, 08:02
a1+a2+a3+a4=240 Statement 1: a3=51 a3+a4=194 a4=143 so a1+a2=46 so both ae less than 50
Statement 2 a2+a3/2=50 a2+a3=100 a1+a4=140 since a2 and a3 are taken for median so a1 is less than a2 and a3.Hence less than 50 Sufficient
So D



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Re: M0828 [#permalink]
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04 Jun 2016, 23:01
Bunuel wrote: If the average of four distinct positive integers is 60, how many integers of these four are less than 50?
(1) The median of the three largest integers is 51 and the sum of two largest integers is 190.
(2) The median of the four integers is 50. Dear bunuel, Can you post more of such questions??



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Re: M0828 [#permalink]
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05 Jun 2016, 03:06



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Re M0828 [#permalink]
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02 Jul 2016, 22:44
I think this is a highquality question and I agree with explanation.
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Re M0828 [#permalink]
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06 Jul 2016, 04:06
I think this is a highquality question and I agree with explanation.



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Re: M0828 [#permalink]
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02 Oct 2016, 19:46
I don't know if I'm reading the same question that the explanation...
If the average of four distinct positive integers is 60, how many integers of these four are less than 50? (1) The median of the three largest integers is 51 and the sum of two largest integers is 190. (2) The median of the four integers is 50.
(1) Sufficient > 'a','b' and 'c'> 50 so 3 integers are less than 50. (2) Insufficient> 'a','b' are less than 50, 'c' could be more o less than 50. So answer could be 2 or 3
Can anyone explain me what I'm missing?



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Re: M0828 [#permalink]
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03 Oct 2016, 06:42
GiancarloGV wrote: I don't know if I'm reading the same question that the explanation...
If the average of four distinct positive integers is 60, how many integers of these four are less than 50? (1) The median of the three largest integers is 51 and the sum of two largest integers is 190. (2) The median of the four integers is 50.
(1) Sufficient > 'a','b' and 'c'> 50 so 3 integers are less than 50. (2) Insufficient> 'a','b' are less than 50, 'c' could be more o less than 50. So answer could be 2 or 3
Can anyone explain me what I'm missing? (2) The median of the four integers is 50. The median of a set with even number of terms is the average of two middle terms, so \(\text{median}=\frac{b+c}{2}=50\). Since given that \(b \lt c\) then \(b \lt 50 \lt c\), so both \(a\) and \(b\) are less than 50. Sufficient.
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New to the Math Forum? Please read this: Ultimate GMAT Quantitative Megathread  All You Need for Quant  PLEASE READ AND FOLLOW: 12 Rules for Posting!!! Resources: GMAT Math Book  Triangles  Polygons  Coordinate Geometry  Factorials  Circles  Number Theory  Remainders; 8. Overlapping Sets  PDF of Math Book; 10. Remainders  GMAT Prep Software Analysis  SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS)  Tricky questions from previous years.
Collection of Questions: PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.
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Re: M0828 [#permalink]
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11 Feb 2018, 19:42
BunuelWhat if the numbers are x1,x2,x3,x4 where x2=50 and x3=51? Then clearly (2) would be insufficient. Could you please clarify. Thanks, ucb2k7



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Re: M0828 [#permalink]
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11 Feb 2018, 20:58










