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Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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09 Dec 2015, 20:29
There is a sequence An such that A1=2, A2=5, and An=An−1An−2,when n is an integer greater than 2. What is the value of A149? A1 = 2 A2 = 5 A3 = 5/2 A4= 1/2 A5 = 1/5 A6 = 2/5 A7 = 2 A8 = 5 The numbers are repeating after six steps. The closest multiple of 6 to 149 is 144 . We are 5 five short to 149 . So A149 = A5 Which is 1/5 so the answer is E



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Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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10 Dec 2015, 12:04
I would go with option 'C' i.e/ 2.5. Please advise if the answer is correct.
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Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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10 Dec 2015, 22:55
A1=2 A2=5 A3=A2/A1=5/2=2.5 A4=A3/A2=2.5/5=1/2=0.5 A5=A4/A3=0.5/2.5=1/5=0.2 A6=A5/A4=0.2/0.5=2/5=0.4 A7=A6/A5=0.4/0.2=2
A8=A7/A6=2/0.4=5 After every 6 terms the numbers are repeating, so to find A149 divide 149 by 6 & u get a remainder 5.
So A149=A5=1/5



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Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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11 Dec 2015, 03:12
Answer is E, i.e. 1/5



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Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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11 Dec 2015, 10:54
A1=2, A2=5, and An=An−1/An−2
A3=A2/A1 A4=A3/A2=A2/A1*A2 = 1/A1 A5=A4/A3= 1/A2 A6=A5/A4= A1/A2 A7= A6/A5=A1 A8=A7/A6=A2 A9=A8/A7=A2/A1
A3=A9=A2/A1 So the sequence repeats at A3,A9,A15,A21........and goes on till A147 Therefore A147= A2/A1 A148=1/A1 A149= 1/A2
A2=5 and 1/A2= 1/5 Therefore answer is 1/5 and choice E.



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Math Revolution and GMAT Club Contest! There is a sequence An such
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14 Dec 2015, 08:13
Bunuel wrote: Math Revolution and GMAT Club Contest Starts! QUESTION #8:There is a sequence \(A_n\) such that \(A_1=2\), \(A_2=5\), and \(A_n=\frac{A_{n1}}{A_{n2}}\),when n is an integer greater than 2. What is the value of \(A_{149}\)? A. 2 B. 5 C. 2.5 D. 1/2 E. 1/5 Check conditions below: Math Revolution and GMAT Club ContestThe Contest Starts November 28th in Quant Forum We are happy to announce a Math Revolution and GMAT Club Contest For the following four (!) weekends we'll be publishing 4 FRESH math questions per weekend (2 on Saturday and 2 on Sunday). To participate, you will have to reply with your best answer/solution to the new questions that will be posted on Saturday and Sunday at 9 AM Pacific. Then a week later, the forum moderator will be selecting 2 winners who provided most correct answers to the questions, along with best solutions. Those winners will get 6months access to GMAT Club Tests. PLUS! Based on the answers and solutions for all the questions published during the project ONE user will be awarded with ONE Grand prize: PS + DS course with 502 videos that is worth $299! All announcements and winnings are final and no whining GMAT Club reserves the rights to modify the terms of this offer at any time. NOTE: Test Prep Experts and Tutors are asked not to participate. We would like to have the members maximize their learning and problem solving process.
Thank you! MATH REVOLUTION OFFICIAL SOLUTION:Generally it is best to substitute in solving sequence questions. The sequence for this question is, \(A_1=2\), \(A_2=5\), \(A_3=\frac{A_2}{A_1}=\frac{5}{2}\), \(A_4=\frac{A_3}{A_2}=(5/2)/5=\frac{1}{2}\), \(A_5=\frac{1}{5}\) and \(A_6=\frac{2}{5}\). This means \(A_{n+6}=A_n\). Then, if we divide \(149=6*24+5\) by 6, the remainder is 5. So, \(A_{149}=A_6*24+5=A_5=\frac{1}{5}\) and E is a correct answer.
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Math Revolution and GMAT Club Contest! There is a sequence An such
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18 Feb 2017, 00:50
Bunuel wrote: Bunuel wrote: Math Revolution and GMAT Club Contest Starts! QUESTION #8:There is a sequence \(A_n\) such that \(A_1=2\), \(A_2=5\), and \(A_n=\frac{A_{n1}}{A_{n2}}\),when n is an integer greater than 2. What is the value of \(A_{149}\)? A. 2 B. 5 C. 2.5 D. 1/2 E. 1/5 Check conditions below: Math Revolution and GMAT Club ContestThe Contest Starts November 28th in Quant Forum We are happy to announce a Math Revolution and GMAT Club Contest For the following four (!) weekends we'll be publishing 4 FRESH math questions per weekend (2 on Saturday and 2 on Sunday). To participate, you will have to reply with your best answer/solution to the new questions that will be posted on Saturday and Sunday at 9 AM Pacific. Then a week later, the forum moderator will be selecting 2 winners who provided most correct answers to the questions, along with best solutions. Those winners will get 6months access to GMAT Club Tests. PLUS! Based on the answers and solutions for all the questions published during the project ONE user will be awarded with ONE Grand prize: PS + DS course with 502 videos that is worth $299! All announcements and winnings are final and no whining GMAT Club reserves the rights to modify the terms of this offer at any time. NOTE: Test Prep Experts and Tutors are asked not to participate. We would like to have the members maximize their learning and problem solving process.
Thank you! MATH REVOLUTION OFFICIAL SOLUTION:Generally it is best to substitute in solving sequence questions. The sequence for this question is, \(A_1=2\), \(A_2=5\), \(A_3=\frac{A_2}{A_1}=\frac{5}{2}\), \(A_4=\frac{A_3}{A_2}=(5/2)/5=\frac{1}{2}\), \(A_5=\frac{1}{5}\) and \(A_6=\frac{2}{5}\). This means \(A_{n+6}=A_n\). Then, if we divide \(149=6*24+5\) by 6, the remainder is 5. So, \(A_{149}=A_6*24+5=A_5=\frac{1}{5}\) and E is a correct answer. Dear Bunuel, \(A_{149}=A_6*24+5=A_5=\frac{1}{5}\)Does we conclude \(A_{149}=A_{5}\) by obtaining the remainder equal to \(5\)?
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Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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18 Feb 2017, 00:57
ziyuenlau wrote: Bunuel wrote: Bunuel wrote: Math Revolution and GMAT Club Contest Starts! QUESTION #8:There is a sequence \(A_n\) such that \(A_1=2\), \(A_2=5\), and \(A_n=\frac{A_{n1}}{A_{n2}}\),when n is an integer greater than 2. What is the value of \(A_{149}\)? A. 2 B. 5 C. 2.5 D. 1/2 E. 1/5 Check conditions below: Math Revolution and GMAT Club ContestThe Contest Starts November 28th in Quant Forum We are happy to announce a Math Revolution and GMAT Club Contest For the following four (!) weekends we'll be publishing 4 FRESH math questions per weekend (2 on Saturday and 2 on Sunday). To participate, you will have to reply with your best answer/solution to the new questions that will be posted on Saturday and Sunday at 9 AM Pacific. Then a week later, the forum moderator will be selecting 2 winners who provided most correct answers to the questions, along with best solutions. Those winners will get 6months access to GMAT Club Tests. PLUS! Based on the answers and solutions for all the questions published during the project ONE user will be awarded with ONE Grand prize: PS + DS course with 502 videos that is worth $299! All announcements and winnings are final and no whining GMAT Club reserves the rights to modify the terms of this offer at any time. NOTE: Test Prep Experts and Tutors are asked not to participate. We would like to have the members maximize their learning and problem solving process.
Thank you! MATH REVOLUTION OFFICIAL SOLUTION:Generally it is best to substitute in solving sequence questions. The sequence for this question is, \(A_1=2\), \(A_2=5\), \(A_3=\frac{A_2}{A_1}=\frac{5}{2}\), \(A_4=\frac{A_3}{A_2}=(5/2)/5=\frac{1}{2}\), \(A_5=\frac{1}{5}\) and \(A_6=\frac{2}{5}\). This means \(A_{n+6}=A_n\). Then, if we divide \(149=6*24+5\) by 6, the remainder is 5. So, \(A_{149}=A_6*24+5=A_5=\frac{1}{5}\) and E is a correct answer. Dear Bunuel, \(A_{149}=A_6*24+5=A_5=\frac{1}{5}\)Does we conclude \(A_{149}=A_{5}\) by obtaining the remainder equal to \(5\)? The sequence goes in blocks of 6 {2, 5, 5/2, 1/2, 1/5, 2/5} {2, 5, 5/2, 1/2, 1/5, 2/5} {2, 5, 5/2, 1/2, 1/5, 2/5}... 149 is a multiple of 6 (144) plus 5, thus A149 equals to 5th number in the pattern, which is 1/5.
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Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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01 Jul 2019, 21:23
Bunuel wrote: Math Revolution and GMAT Club Contest Starts! QUESTION #8:There is a sequence \(A_n\) such that \(A_1=2\), \(A_2=5\), and \(A_n=\frac{A_{n1}}{A_{n2}}\),when n is an integer greater than 2. What is the value of \(A_{149}\)? A. 2 B. 5 C. 2.5 D. 1/2 E. 1/5 Check conditions below: Math Revolution and GMAT Club ContestThe Contest Starts November 28th in Quant Forum We are happy to announce a Math Revolution and GMAT Club Contest For the following four (!) weekends we'll be publishing 4 FRESH math questions per weekend (2 on Saturday and 2 on Sunday). To participate, you will have to reply with your best answer/solution to the new questions that will be posted on Saturday and Sunday at 9 AM Pacific. Then a week later, the forum moderator will be selecting 2 winners who provided most correct answers to the questions, along with best solutions. Those winners will get 6months access to GMAT Club Tests. PLUS! Based on the answers and solutions for all the questions published during the project ONE user will be awarded with ONE Grand prize: PS + DS course with 502 videos that is worth $299! All announcements and winnings are final and no whining GMAT Club reserves the rights to modify the terms of this offer at any time. NOTE: Test Prep Experts and Tutors are asked not to participate. We would like to have the members maximize their learning and problem solving process.
Thank you! A1 =2 A2 = 5 A3 =5/2 A4 = 1/2 A5 = 1/5 A6 = 2/5 A7 = 2 A8 = 5 We see that A7 = A1 & A8 = A2, in general A(6+k) = Ak 149 = 6*24 + 5 A149 = A5 = 1/5 IMO E




Re: Math Revolution and GMAT Club Contest! There is a sequence An such
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