Ex 5.2, 17 - Find 20th term from last term of AP 3, 8, 13

Ex 5.2, 17 - Chapter 5 Class 10 Arithmetic Progressions - Part 2

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Ex 5.2, 17 Find the 20th term from the last term of the A.P. 3, 8, 13, …, 253 Given AP 3, 8, 13, …, 253 Now, 20th term from last term of AP 3, 8, 13, …, = 20th term of AP 253, 248, 243, …., 8, 3 Thus, our AP is 253, 248, 243, …., 8, 3 Here a = 253 d = 248 – 253 = −5 We need to find 20th term n = 20 Now, an = a + (n – 1) d Putting values an = 253 + (20 – 1) × (−5) an = 253 + 19 × (−5) an = 253 − 95 an = 158 So the 20th term from the Last is 158

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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