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Saturday, 31 October

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JEE Main 2021 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 31 August 2021, Shift 2, Maths Q65

Question 65 of 90 in this shift, Maths question 5 of 30, Section A.

Let

\mathrm{a_1, a_2, a_3, ...}

be an A.P. If

\frac{\mathrm{a_1+a_2+...+a_{10}}}{\mathrm{a_1+a_2+...+a_p}} = \frac{100}{\mathrm{p}^2}

,

\mathrm{p} \neq 10

, then

\frac{\mathrm{a_{11}}}{\mathrm{a_{10}}}

is equal to :

(1) $\frac{121}{100}$
(2) $\frac{21}{19}$ Official answer
(3) $\frac{19}{21}$
(4) $\frac{100}{121}$

Official answer

Option 2

NTA final key.

Chapter: Sequences and Series
Topic: AP and GP
Idea tested: AP Recognition from Quadratic Sum

Same idea in other shifts

Asked 2× in all

5 Apr 2026, Shift 1 · Q2Let the sum of the first $n$ terms of an A.P. be $3n^2 + 5n$ . Then the sum of squares of the first 10 terms of the A.P. is:EasySingle correct

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.