Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.

Question

KnowledgeBoat · Accepted Answer

Let first term of A.P. be a. Given, Common difference (d) = 7 By formula, a_n = a + (n - 1)d Given, ⇒ a₂₂ = 149 ⇒ a + 7(22 - 1) = 149 ⇒ a + 7 × 21 = 149 ⇒ a + 147 = 149 ⇒ a = 149 - 147 = 2. Last term (l) = 22nd term = 149 By formula, Sum of A.P. (S) = Substituting values we get : Hence, sum of first 22 terms = 1661.

Mathematics

Find the sum of first 22 terms of an AP in which d = 7 and 22nd term is 149.

AP

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