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Consider an arithmetic sequence whose 7th term is 34 and 15th term is 66.a. Find the common difference,b. Find the 20th term. |
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Answer» a. 15th term can be obtained by adding 7th term ‘ and 8 times the common difference. x15 = x7 + 8d 66 = 34 + 8d 8d = 66 – 34 = 32 d = \(\frac{32}{8}\) = 4 d. 20th term can be obtained by adding 15th term and 5 times the common difference. x20 = x15 + 8d = 66 + 5 × 4 = 86 |
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