JEE Main 2021 · MathsNumerical answerNumerical valueMediumMulti-step

JEE Main 26 August 2021, Shift 2, Maths Q90

Question 90 of 90 in this shift, Maths question 30 of 30, Section B.

Let

\mathrm{a}_1,\mathrm{a}_2,\ldots,\mathrm{a}_{10}

be an AP with common difference

-3

and

\mathrm{b}_1,\mathrm{b}_2,\ldots,\mathrm{b}_{10}

be a GP with common ratio 2. Let

\mathrm{c}_{\mathrm{k}}=\mathrm{a}_{\mathrm{k}}+\mathrm{b}_{\mathrm{k}}

\mathrm{k}=1,2,\ldots,10

. If

\mathrm{c}_2=12

and

\mathrm{c}_3=13

, then

\sum_{\mathrm{k}=1}^{10}\mathrm{c}_{\mathrm{k}}

is equal to __________.

Official answer

2021

NTA final key.

Chapter: Sequences and Series
Topic: AP and GP
Idea tested: AP Sum of n terms

Same idea in other shifts

Asked 31× in all

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2 Apr 2025, Shift 1 · Q19Let $a_1, a_2, a_3,\ldots$ be in an A.P. such that $\sum_{k=1}^{12}a_{2k-1}=-\frac{72}{5}a_1$ , $a_1\neq0$ . If $\sum_{k=1}^{n}a_k=0$ , then…MediumSingle correct
7 Apr 2025, Shift 2 · Q6Let $a_n$ be the $n^{\mathrm{th}}$ term of an A.P. If $S_n=a_1+a_2+a_3+\ldots+a_n=700$ , $a_6=7$ and $S_7=7$ , then $a_n$ is equal to :MediumSingle correct
5 Apr 2024, Shift 1 · Q25Let $a_1, a_2, a_3, \ldots$ be in an arithmetic progression of positive terms. Let…HardNumerical value
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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.