WBJEE · Maths · Sequences and Series
If the sum of ' \(n\) ' terms of an A.P. is \(3 n^2+5 n\) and its \(m\)th term is 164 , then the value of \(m\) is
- A \(26\)
- B \(27\)
- C \(28\)
- D \(29\)
Answer & Solution
Correct Answer
(B) \(27\)
Step-by-step Solution
Detailed explanation
\(\mathrm{t}_1=\mathrm{S}_1=8\) \(t_1+t_2=S_2=22 \text { So, } t_2=14 \Rightarrow d=6\) Given, \(a+(m-1) d=164 \Rightarrow 8+(m-1) 6=164 \Rightarrow m=27\)
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