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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

Best Answer 

 #1
avatar
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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
 #1
avatar
+1
Best Answer

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
avatar+1442 
+1

Thanks so much :D


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