|
Author |
Message |
|
TAGS:
|
|
|
GMAT Club Legend
Joined: 07 Jun 2014
Posts: 4749
WE: Business Development (Energy and Utilities)
Followers: 93
Kudos [?]:
1659
[0], given: 396
|
The sequence of numbers S={s1,s2,s3…} is defined by s1 = 2, [#permalink]
 27 Mar 2018, 16:17
Question Stats:
75% (00:23) correct
25% (00:00) wrong based on 4 sessions
The sequence of numbers S={s1,s2,s3…} is defined by \(s_{1} = 2\), \(s_{2} = 10\), and \(S_{n}=S_{n-1}^{S_{n-2}}\)for each positive integer n greater than or equal to 3. For example, s3 = 102. What is the greatest value of n for which sn has 2,000 or fewer digits? A. 100 B. 20 C. 5 D. 4 E. 3 Drill 1
Question: 10
Page: 548
_________________
Sandy
If you found this post useful, please let me know by pressing the Kudos Button
Try our free Online GRE Test
|
|
|
|
|
|
|
Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1
Kudos [?]:
29
[1]
, given: 4
|
Re: The sequence of numbers S={s1,s2,s3…} is defined by s1 = 2, [#permalink]
27 Mar 2018, 21:34
1
This post received
KUDOS
sandy wrote: The sequence of numbers S={s1,s2,s3…} is defined by s1 = 2, s2 = 10, and for each positive integer n greater than or equal to 3. For example, s3 = 102. What is the greatest value of n for which sn has 2,000 or fewer digits? A. 100 B. 20 C. 5 D. 4 E. 3 Drill 1
Question: 10
Page: 548 I think something is missing especially the defintion of the the sequence, check it out please~
|
|
|
|
|
|
GMAT Club Legend
Joined: 07 Jun 2014
Posts: 4749
WE: Business Development (Energy and Utilities)
Followers: 93
Kudos [?]:
1659
[0], given: 396
|
Re: The sequence of numbers S={s1,s2,s3…} is defined by s1 = 2, [#permalink]
04 Apr 2018, 15:42
Sorry about that! Fixed..
_________________
Sandy
If you found this post useful, please let me know by pressing the Kudos Button
Try our free Online GRE Test
|
|
|
|
|
|
GMAT Club Legend
Joined: 07 Jun 2014
Posts: 4749
WE: Business Development (Energy and Utilities)
Followers: 93
Kudos [?]:
1659
[0], given: 396
|
Re: The sequence of numbers S={s1,s2,s3…} is defined by s1 = 2, [#permalink]
04 Apr 2018, 15:46
ExplanationDecoding the definition of the sequence tells you that, to find the value of each term, you take the previous term, and raise it to the power of the term before it. You know \(S_{3}=10^2=100\) and \(S_{4}=100^{10}=10^{20}\) and \(S_{5}=(10^{20})^{100}=10^{2000}\). So \(S_{4}\) is the digit 1 followed by twenty zeroes, which is a total of 21 digits, and \(S_{5}\) is the digit 1 followed by 2,000 zeroes, for a total of 2,001 digits. So the fourth term is the one that meets the condition set forth in the question, and the answer is choice (D).
_________________
Sandy
If you found this post useful, please let me know by pressing the Kudos Button
Try our free Online GRE Test
|
|
|
|
|
|
|
Re: The sequence of numbers S={s1,s2,s3…} is defined by s1 = 2,
[#permalink]
04 Apr 2018, 15:46
|
|
|
|
|
|
|
|
|
close
