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Julie is putting \(M\) marbles in a row in a repeating pattern: blue, white, red, green, black, yellow, pink. If the row begins with blue marble and ends with red marble, then which of the following could be the value of \(M\)? A. 22 B. 30 C. 38 D. 46 E. 54
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Re M2615
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16 Sep 2014, 01:25
Official Solution:Julie is putting \(M\) marbles in a row in a repeating pattern: blue, white, red, green, black, yellow, pink. If the row begins with blue marble and ends with red marble, then which of the following could be the value of \(M\)? A. 22 B. 30 C. 38 D. 46 E. 54 There are total of 7 different color marbles in a pattern. Now, as the row begins with blue marble and ends with red marble (so ends with 3rd marble in a pattern) then \(M=7k+3\). The only answer choice which is multiple of 7 plus 3 is \(38=35+3\). Answer: C
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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: M2615
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07 Aug 2015, 04:26
Hi Bunuel, Pls. correct where my understanding is going wrong? Its given that the marbles are arranged in a row in a repeating pattern starting with Blue, white.....and ending with red marble. So, we have blue, white, red, green, black, yellow, pink, blue, white, red (Totally 10 Marbles in each row) So my question to you if that is the case, then why cannot 30 be the total number of Marbles since it is divisble by 10. My understanding is that the marbles are arranged in each row as below: blue, white, red, green, black, yellow, pink, blue, white, red > Row1 (10 Marbles) blue, white, red, green, black, yellow, pink, blue, white, red > Row2 (10 Marbles) blue, white, red, green, black, yellow, pink, blue, white, red > Row3 (10 Marbles) Vijay Bunuel wrote: Official Solution:
Julie is putting \(M\) marbles in a row in a repeating pattern: blue, white, red, green, black, yellow, pink. If the row begins with blue marble and ends with red marble, then which of the following could be the value of \(M\)?
A. 22 B. 30 C. 38 D. 46 E. 54
There are total of 7 different color marbles in a pattern. Now, as the row begins with blue marble and ends with red marble (so ends with 3rd marble in a pattern) then \(M=7k+3\). The only answer choice which is multiple of 7 plus 3 is \(38=35+3\).
Answer: C



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Re: M2615
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07 Aug 2015, 04:33
Sorry Bunuel, I got my mistake. I think I have ignored the word "in a row" in the question. Realized this only after I posted this query. Vijay svijayaug12 wrote: Hi Bunuel, Pls. correct where my understanding is going wrong? Its given that the marbles are arranged in a row in a repeating pattern starting with Blue, white.....and ending with red marble. So, we have blue, white, red, green, black, yellow, pink, blue, white, red (Totally 10 Marbles in each row) So my question to you if that is the case, then why cannot 30 be the total number of Marbles since it is divisble by 10. My understanding is that the marbles are arranged in each row as below: blue, white, red, green, black, yellow, pink, blue, white, red > Row1 (10 Marbles) blue, white, red, green, black, yellow, pink, blue, white, red > Row2 (10 Marbles) blue, white, red, green, black, yellow, pink, blue, white, red > Row3 (10 Marbles) Vijay Bunuel wrote: Official Solution:
Julie is putting \(M\) marbles in a row in a repeating pattern: blue, white, red, green, black, yellow, pink. If the row begins with blue marble and ends with red marble, then which of the following could be the value of \(M\)?
A. 22 B. 30 C. 38 D. 46 E. 54
There are total of 7 different color marbles in a pattern. Now, as the row begins with blue marble and ends with red marble (so ends with 3rd marble in a pattern) then \(M=7k+3\). The only answer choice which is multiple of 7 plus 3 is \(38=35+3\).
Answer: C



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Re M2615
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12 Oct 2015, 23:39
I think this is a highquality question and the explanation isn't clear enough, please elaborate.



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Re: M2615
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Re: M2615
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16 Oct 2015, 11:25
Bunuel wrote: Cadaver wrote: I think this is a highquality question and the explanation isn't clear enough, please elaborate. Can you please be a little bit more specific? Which part is not clear? Thank you. couldn't understand the question could you please provide a detailed explanation



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Cadaver wrote: I think this is a highquality question and the explanation isn't clear enough, please elaborate. You start placing different color marbles in a row...starting with blue white red green Black yellow pink.and in the same row the last marble has to be red,so you have to again start repeating this pattern until you get the red marble. {blue white red green Black yellow pink} blue white Red it would be a multiple of seven + 3 additional tiles=7k+3 From the answer choices,only 38 satisfies this equation.



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Re: M2615
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07 Aug 2018, 22:21
blue, white, red, green, black, yellow, pink. blue, white, red, green, black, yellow, pink. blue, white, red, green, black, yellow, pink. blue (A. 22), white, red, green, black, yellow, pink. blue, white (B, 30), red, green, black, yellow, pink. blue, white, red (C 38), green, black, yellow, pink. blue, white, red, green (D 46), black, yellow, pink. blue, white, red, green, black (E 54), yellow, pink. blue, white, red, green, black, yellow, pink.
this makes more sense? i made the mistake of thinking it's B too. but when you lay them out the right answer is C



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Re: M2615
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29 Aug 2018, 12:41
Bunuel wrote: Official Solution:
Julie is putting \(M\) marbles in a row in a repeating pattern: blue, white, red, green, black, yellow, pink. If the row begins with blue marble and ends with red marble, then which of the following could be the value of \(M\)?
A. 22 B. 30 C. 38 D. 46 E. 54
There are total of 7 different color marbles in a pattern. Now, as the row begins with blue marble and ends with red marble (so ends with 3rd marble in a pattern) then \(M=7k+3\). The only answer choice which is multiple of 7 plus 3 is \(38=35+3\).
Answer: C This is a good explanation, but to make it clearer for some: Consider the string of Blue, White, Red, Green, Black, Yellow and Pink marbles is 7 long. Since the string repeats, you need to divide all of the answers by seven. Then note how the actual string starts and ends. It starts with Blue (position #1), and ends with Red (position #3). Therefore you are looking for an answer that will be a multiple of seven, and have three left over (remainder 3). To solve, divide all of the answers by 7, and when the remainder is 3 you have an answer. You can also just count out until you find one that matches.










