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7. The 16th term of an AP is 1 more than twice its 8th term. If the 12h termterm of an AP is 1 more than twice its 8th term. If the 12th termof the AP is 47, then find its nth term. |
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Answer» Solution:-Given : a₁₂ = 47 or a + 11d = 47a₁₆ = a + 15d and a₈ = a +7dNow, according to the question2(a + 7d) + 1 = a + 15d2a + 14d + 1 = a + 15d2a - a = 15d - 14d - 1a = d -1 .................(1)Substituting the value of 'a' in a + 11d = 47, we getd - 1 + 11d = 4712d = 47 + 112d = 48d = 4Substituting the value of 'd' in a + 11d = 47, we geta + 11*4 = 47a = 47 - 44a = 3Nownth term = a + (n - 1)d= 3 + (n - 1)4= 3 + 4n - 4nth term = 4n - 1 |
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