Mathematics · 2020
JEE Main · 4 September 2020, Shift 2 · Q57
Let a_1, a_2, ….., a_n be a given A.P. whose common difference is an integer and S_n = a_1+ a_2+…..+ a_n. If a_1=1, a_n =300 and 15 ≤ n ≤ 50, then…
Let $\displaystyle \mathrm{a}_1, \mathrm{a}_2, \ldots . ., \mathrm{a}_{\mathrm{n}}$ be a given A.P. whose common difference is an integer and $\displaystyle \mathrm{S}_{\mathrm{n}}=\mathrm{a}_1+\mathrm{a}_2+\ldots . .+\mathrm{a}_{\mathrm{n}}$. If $\displaystyle \mathrm{a}_1=1, \mathrm{a}_{\mathrm{n}}=300$ and $\displaystyle 15 \leq \mathrm{n} \leq 50$, then the ordered pair $\displaystyle \left(\mathrm{S}_{\mathrm{n}-4}, \mathrm{a}_{\mathrm{n}-4}\right)$ is equal to :
Official answer
(1)
$\displaystyle (2490,248)$
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JEE Main 2020 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.