Find the number of terms in the series and then find the sum using the alternate formula. 11 + 19 + 27 + 35 + 43 + . . . + 163 A) n = 19; S₂₀ = 1583 B) n = 19; S₂₀ = 1591 C) n = 20; S₂₀ = 1740 D) n = 21; S₂₀ = 1911

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To find the number of terms, we need to find the common difference first. Common difference = 19 - 11 = 8 The first term is 11 and the last term is 163. So, 163 = 11 + (n - 1)8 Solving for n, we get n = 20. Now, to find the sum using the alternate formula, we have S₂₀ = (n/2)(first term + last term) S₂₀ = (20/2)(11 + 163) = 1740 Therefore, the answer is C.

Find the Number of Terms in the Series and Then