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The first and thirteenth terms of an arithmetic sequence are $\frac79$ and $\frac45$, respectively. What is the seventh term?

Jan 18, 2020

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I'm assuming that this: $\frac79$ and $\frac45$, means: 7/9 and 4/5 ??

If so, the nth term =First term + [common difference * Term number - 1]

The 13th term =7/9 + [D * (13 - 1)]

4/5 =7/9 + 12D, solve for D

D = 1 / 540

7th term =7/9 + 1 /540 * 6

7th term = 71 / 90

Jan 19, 2020