SOLUTION: The sum of the terms of a finite arithmetic series is 624. If the sum of the 1st term and last term is 48, how many terms are there in the sequence?

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Question 892724: The sum of the terms of a finite arithmetic series is 624.
If the sum of the 1st term and last term is 48,
how many terms are there in the sequence?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
By the given, S%5Bn%5D+=+%28n%2F2%29%2A%28a%5B1%5D+%2B+a%5Bn%5D%29=624
But it is also given that a%5B1%5D+%2B+a%5Bn%5D+=+48
==>+%28n%2F2%29%2A%2848%29=624
==> n = 26