SOLUTION: an arithmetic sequence formed of 11 terms ,its middle term equals 20. find the sum of it's terms ,and find a sequence which verifies the equation.

Question 970618: an arithmetic sequence formed of 11 terms ,its middle term equals 20. find the sum of it's terms ,and find a sequence which verifies the equation.

Answer by josgarithmetic(39618) (Show Source): You can put this solution on YOUR website!
You can pick any common difference you want. To be simple, you can pick d=1. The terms will extend to 20+5*1 and to 20-5*1; which are 25 and 15. The general terms would be .

First term is 15 for when n=1.
You can either derive or look-up the formula for SUM of an arithmetic sequence.
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