SOLUTION: Find the sum of the first 40 terms of the arithmetic sequence: 13, 19, 25, 31, ...

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Question 453514: Find the sum of the first 40 terms of the arithmetic sequence: 13, 19, 25, 31, ...
Answer by stanbon(75887) About Me  (Show Source):
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Find the sum of the first 40 terms of
the arithmetic sequence: 13, 19, 25, 31, ...
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Find the 40th term:
a(40) = 13 + (39)6 = 247
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Find the sum:
S(40) = (40/2)(13+247) = 20*260 5200
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Cheers,
Stan H.