JEE Mains · Maths · STD 11 - 8. sequence and series
Let \({a_1},{a_2},.......,{a_{30}}\) be an \(A.P.\), \(S = \sum\limits_{i = 1}^{30} {{a_i}} \) and \(T = \sum\limits_{i = 1}^{15} {{a_{2i - 1}}} \).If \({a_5} = 27\) and \(S - 2T = 75\) , then \(a_{10}\) is equal to
- A \(52\)
- B \(57\)
- C \(47\)
- D \(42\)
Answer & Solution
Correct Answer
(A) \(52\)
Step-by-step Solution
Detailed explanation
\(S = \sum\limits_{i - 1}^{30} {{a_i}} \,\,\,\,,T = \sum\limits_{i - 1}^{15} {{a_{2i - 1}}} \,\,\,\,\,,{a_5} = 27,S - 2T = 75\) Let \({a_i} = a + \left( {i - 1} \right)D\) \(S = {a_1} + {a_2} + {a_3} + ........... + {a_{30}}\)…
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