Multiple choice

Find the sum of the following arithmetic series: $2 , 4 ,6 , 8 ,...... (15 $ terms).

  1. $210$
  2. $220$
  3. $230$
  4. $240$
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D Correct answer
Explanation

Arithmetic series: 2, 4, 6... (15 terms). Sum = (n/2) * (2a + (n-1)d) = (15/2) * (2*2 + 14*2) = (15/2) * (4 + 28) = (15/2) * 32 = 15 * 16 = 240.

AI explanation

Use the arithmetic series sum formula Sn = n/2 * (2a + (n-1)d). The first term a is 2, the common difference d is 2 (4 - 2), and the number of terms n is 15. Substituting these values gives S15 = 15/2 * (2*2 + (15-1)*2) = 15/2 * (4 + 28) = 15/2 * 32 = 15 * 16 = 240.

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