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A sequence of numbers is represented as a1, a2, a3, …, an. E
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02 May 2019, 02:43
02 May 2019, 02:43
Expert Reply
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Question Stats:
67% (02:14) correct
32% (02:08) wrong based on 40 sessions
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A sequence of numbers is represented as \(a_1\), \(a_2\), \(a_3\), …, \(a_n\). Each number in the sequence (except the first and the last) is the mean of the two adjacent numbers in the sequence. If \(a_1 = 1\) and \(a_5 = 3\), what is the value of \(a_3\) ?
(A) \(\frac{1}{2}\)
(B) \(1\)
(C) \(\frac{3}{2}\)
(D) \(2\)
(E) \(\frac{5}{2}\)
(A) \(\frac{1}{2}\)
(B) \(1\)
(C) \(\frac{3}{2}\)
(D) \(2\)
(E) \(\frac{5}{2}\)
Re: A sequence of numbers is represented as a1, a2, a3, …, an. E
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17 Apr 2020, 04:16
17 Apr 2020, 04:16
Expert Reply
a1=1
a5=3
a2=a1+a3/2
a3=a2+a4/2
a4=a3+a5/2
solve for a2 in terms of a3
a2=a3+1/2
and
a4=a3+3/2
so 2a3= a3+1/2 + 3+a3/2
solve for a3= 2
D is the answer
a5=3
a2=a1+a3/2
a3=a2+a4/2
a4=a3+a5/2
solve for a2 in terms of a3
a2=a3+1/2
and
a4=a3+3/2
so 2a3= a3+1/2 + 3+a3/2
solve for a3= 2
D is the answer
Re: A sequence of numbers is represented as a1, a2, a3, , an. E
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04 Jul 2024, 12:47
04 Jul 2024, 12:47
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Thanks to another GRE Prep Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
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