Math - Sum of a Series

Find the sum of the series 23 + 18 + 13 + . . .+ (-82)

A) -590
B) 590
C) -649
D) 649

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  1. Number of terms
    =(23-(-82))/5+1
    =22

    Sum = (first term + last term)*number of terms / 2
    =(23+(-82))*22/2
    =-59*11
    =-649

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  2. Thanks. Mange to figure it out. Got the same answer as you.

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    posted by Robo123
  3. You're welcome!

    How did you do it?

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