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The sequence \(a_1\), \(a_2\), \(a_3\), \(a_4\), \(a_5\) is such that \(a_n= a_{n-1} + 5\) for \(2\leq n \leq 5\). If \(a_5 = 31\), what is the value of \(a_1\) ?
(A) 1 (B) 6 (C) 11 (D) 16 (E) 21
Problem Solving Question: 67 Category:Algebra Sequences Page: 70 Difficulty: 600
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The sequence a1, a2, a3, a4, a5 is such that an=a(n-1)+5 for
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30 Jan 2014, 00:50
1
SOLUTION
The sequence \(a_1\), \(a_2\), \(a_3\), \(a_4\), \(a_5\) is such that \(a_n= a_{n-1} + 5\) for \(2\leq n \leq 5\). If \(a_5 = 31\), what is the value of \(a_1\) ?
Re: The sequence a1, a2, a3, a4, a5 is such that an=a(n-1)+5 for
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30 Jan 2014, 02:10
1
1
The sequence \(a_1\), \(a_2\), \(a_3\), \(a_4\), \(a_5\) is such that \(a_n= a_{n-1} + 5\) for \(2\leq n \leq 5\). If \(a_5 = 31\), what is the value of \(a_1\) ?
(A) 1 (B) 6 (C) 11 (D) 16 (E) 21
Sol: Given a5=31....and also a5=a4+5 ---> a4=26-----> a3=21----->a2=16 ---->a1=11. Ans C
600 level is okay
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Re: The sequence a1, a2, a3, a4, a5 is such that an=a(n-1)+5 for
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30 Jan 2014, 09:42
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1
This answer can be easily be solve by A.P. The sequence is an A.P. with each term at an increment of 5 from the previous term. So a5 is nothing but a1+20.
Re: The sequence a1, a2, a3, a4, a5 is such that an=a(n-1)+5 for
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18 Mar 2014, 22:12
Bunuel wrote:
SOLUTION
The sequence \(a_1\), \(a_2\), \(a_3\), \(a_4\), \(a_5\) is such that \(a_n= a_{n-1} + 5\) for \(2\leq n \leq 5\). If \(a_5 = 31\), what is the value of \(a_1\) ?
Re: The sequence a1, a2, a3, a4, a5 is such that an=a(n-1)+5 for
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19 Mar 2014, 00:59
1
havoc7860 wrote:
Bunuel wrote:
SOLUTION
The sequence \(a_1\), \(a_2\), \(a_3\), \(a_4\), \(a_5\) is such that \(a_n= a_{n-1} + 5\) for \(2\leq n \leq 5\). If \(a_5 = 31\), what is the value of \(a_1\) ?
Re: The sequence a1, a2, a3, a4, a5 is such that an=a(n-1)+5 for
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26 Mar 2018, 16:34
Quote:
The sequence \(a_1\), \(a_2\), \(a_3\), \(a_4\), \(a_5\) is such that \(a_n= a_{n-1} + 5\) for \(2\leq n \leq 5\). If \(a_5 = 31\), what is the value of \(a_1\) ?
(A) 1 (B) 6 (C) 11 (D) 16 (E) 21
a(5) = 31, so:
a(5) = a(4) + 5
31 = a(4) + 5
26 = a(4)
The pattern is to subtract 5 to obtain the value of the previous term in this recursively-defined sequence.
Thus, a(3) = 21, a(2) =16, and a(1) = 11.
Answer: C
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