Ex 5.3, 6
Last updated at Feb. 25, 2017 by Teachoo
Transcript
Ex 5.3 ,6 The first and the last term of an AP are 17 and 350 respectively. If the common difference is 9, how many terms are there and what is their sum? Given a = 17 , l = 350, d = 9 We need to find how many terms i.e. n and their sum i.e. Sn From (1) and (2) 367× 𝑛/2 = 𝑛/2 (25 + 9n) 367 = 25 + 9n 367 – 25 = 9n 342 = 9n 342/9 = n 38 = n n = 38 Now, we need to find sum Putting value of n in (1) Sum = 367 × 𝑛/2 = 367 × 38/2 = 367 × 19 = 6973
Chapter 5 Class 10 Arithmetic Progressions
Serial order wise
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