Ex 5.3, 3 (ii) - Chapter 5 Class 10 Arithmetic Progressions

Last updated at April 16, 2024 by

Ex 5.3, 3 - Chapter 5 Class 10 Arithmetic Progressions - Part 3

Ex 5.3, 3 - Chapter 5 Class 10 Arithmetic Progressions - Part 4

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Ex 5.3, 3 In an AP (ii) Given a = 7, a13 = 35, find d and S13. Given a = 7, a13 = 35 We need to find d We know that an = a + (n – 1) d Putting a = 7, n = 13 and an = 35 35 = 7 + (13 – 1) × 𝑑 35 = 7 + 12d 35 – 7 = 12d 28 = 12 d 28/12=𝑑 7/3=𝑑 d = 𝟕/𝟑 Now we need to find S13 We can use formula Sn = 𝒏/𝟐 (𝒂+𝒍) Putting n = 13, a = 7, 𝑙 = a13 = 35 = 13/2(7+35) = 13/2 × 42 = 13 × 21 = 273

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Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science and Computer Science at Teachoo