SOLUTION: Here is question: find the sum of all multiples of 4 that are between 14 and 523. Thank for help me

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Question 363369: Here is question: find the sum of all multiples of 4 that are between 14 and 523. Thank for help me
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
a1 = 16 and an = 520. Also, an = a1 + (n-1)d = 16 + (n-1)4 = 4n + 12.
We solve for n. 520 = 4n + 12.
4n = 508, or n = 127. By the formula for the sum of an arithmetic series,
S+=+%28127%2F2%29%2A%2816+%2B+520%29=34036.