SOLUTION: Sum ofthe series 21+22+23......200

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Question 867124: Sum ofthe series 21+22+23......200
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
an = a + (n - 1)d
200 = 21 + (n - 1)1
n=180
S = ½(a + an)n
S = ½(21 + 200)180
S = 19890