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# Short question

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The first and ninth terms of an arithmetic sequence are 2/3 and 4/5, respectively. What is the fifth term?

Thanks so much for all the help!

edited by Guest  Jan 8, 2018

#1
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Nth term = First term + [Number of term - 1] x Common difference.
So, the 9th term is:
4/5 = 2/3 + [9 - 1] x D, solve for D
4/5 - 2/3 = 8D
[12 - 10] / 15 = 8D
2/15 = 8D
D = 1/60
5th term = 2/3 + [5 - 1] x 1/60
= 2/3 + 4/60
=2/3 + 1/15
=11 / 15, which is the 5th term of this sequence.

Guest Jan 8, 2018
Sort:

#1
+1

Nth term = First term + [Number of term - 1] x Common difference.
So, the 9th term is:
4/5 = 2/3 + [9 - 1] x D, solve for D
4/5 - 2/3 = 8D
[12 - 10] / 15 = 8D
2/15 = 8D
D = 1/60
5th term = 2/3 + [5 - 1] x 1/60
= 2/3 + 4/60
=2/3 + 1/15
=11 / 15, which is the 5th term of this sequence.

Guest Jan 8, 2018
#2
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Thanks so much :D

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