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The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
 01 Oct 2012, 05:05
Question Stats:
75% (01:33) correct
24% (00:43) wrong based on 41 sessions
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
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
01 Oct 2012, 05:29
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The average of 10 30 50 is \frac{A = 10+30+50}{3} = 30The second Average must be 5 less : 25. Using common sense or back solve we can obtain the solution. Starting with A because we need a small value in the difference. So, \frac{A = 20+40+15}{3} = 25A is the answer
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
01 Oct 2012, 19:47
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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]
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]
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 30-5=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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PLEASE READ AND FOLLOW: 11 Rules for Posting!!!
RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders
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. NEW!!! ,11 Mixed Questions NEW!!!, 12 Fresh Meat NEW!!!
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. NEW!!!, 11 New DS set. NEW!!!
What are GMAT Club Tests?
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GMAT Club team member
Joined: 02 Sep 2009
Posts: 12077
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Kudos [?]:
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more [#permalink]
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 30-5=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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PLEASE READ AND FOLLOW: 11 Rules for Posting!!!
RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders
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. NEW!!! ,11 Mixed Questions NEW!!!, 12 Fresh Meat NEW!!!
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. NEW!!!, 11 New DS set. NEW!!!
What are GMAT Club Tests?
25 extra-hard Quant Tests
Find out what's new at GMAT Club - latest features and updates
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Re: The average (arithmetic mean) of 10, 30, and 50 is 5 more
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04 Oct 2012, 14:05
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