In an AP, it is given that `S_(5) + S_(7) = 167 "and" S_(10) = 235`, t – InterviewSolution

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1.	In an AP, it is given that `S_(5) + S_(7) = 167 "and" S_(10) = 235`, then find the AP, where `S_(n)` denotes the sum of its first n terms.
Answer» Correct Answer - 1, 6, 11, 16,… `S_(5) + S_(7) = 167 rArr (5)/(2)(2a +4d) + (7)/(2)(2a +6d) = 167` `rArr 12a + 31d = 167 " "…(i)` `S_(10) = 235 rArr (10)/(2) (2a +9d) = 235 rArr 2a + 9d = 47. " "...(ii)` Solve (i) and (ii), we get a = 1 and d = 5.

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