Multiple choice

Find the sum of first 10 terms of the arithmetic series if $a_1 = 2$ and $a_{10} = 22$.

  1. $155$
  2. $120$
  3. $165$
  4. $130$
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B Correct answer
Explanation

Sum of an arithmetic series = (n/2) * (a1 + an). Here, n=10, a1=2, a10=22. Sum = (10/2) * (2 + 22) = 5 * 24 = 120.

AI explanation

Using the sum formula for an arithmetic series, S_n = n/2(a_1 + a_n), we substitute the given values. With n equal to 10, the first term equal to 2, and the tenth term equal to 22, the sum is 10/2(2 + 22). This simplifies to 5 * 24, resulting in a total sum of 120.

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