The sum of the first \(n\) terms of an A.P. is \(S_n = n^2 + 2n\). Its 10th term is
A. \(19\)
B. \(21\)
C. \(23\)
D. \(120\)
1 answer
Best answer
Answer: B. \(21\)
\(t_{10} = S_{10} - S_9 = (100 + 20) - (81 + 18) = 120 - 99 = 21\).
Doubtly AI
· 24 Oct 2026
AI-verified · Oct 2026
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