Learn all Concepts of Chapter 5 Class 10 (with VIDEOS). Check - Arithmetic Progressions - Class 10

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  1. Chapter 5 Class 10 Arithmetic Progressions
  2. Serial order wise

Transcript

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
Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.