Example 11 - Find sum of first 22 terms of AP: 8, 3, -2, ..

Example 11 - Chapter 5 Class 10 Arithmetic Progressions - Part 2

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Example 11 Find the sum of the first 22 terms of the AP : 8, 3, –2, . . . Given 8, 3, –2,………… We have to find sum of first 22 terms . Here, n = 22, a = 8 d = 3 – 8 = –5 Putting there values in formula, Sum = 𝑛/2 [2𝑎+(𝑛−1)𝑑] = 22/2[2 × 8+(22−1)(−5)] = 11[16+(21)(−5)] = 11[16−105] = 11[− 89] = –979

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 13 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.