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Saturday, 31 October

JEE Main 2022 · MathsMultiple choiceSingle correctMediumMulti-step

JEE Main 29 July 2022, Shift 1, Maths Q4

Question 4 of 90 in this shift, Maths question 4 of 30, Section A.

If 1(20−a)(40−a)+1(40−a)(60−a)+…+1(180−a)(200−a)=1256\frac{1}{(20 - a)(40 - a)} + \frac{1}{(40 - a)(60 - a)} + \ldots + \frac{1}{(180 - a)(200 - a)} = \frac{1}{256}, then the maximum value of a is :
  1. (1)198
  2. (2)202
  3. (3)212Official answer
  4. (4)218

Official answer

Option 3

NTA final key.

Same idea in other shifts

Asked 19× in all
  1. 5 Apr 2026, Shift 1 · Q5∑n=110(528n(n+1)(n+2))\sum_{n=1}^{10}\left(\frac{528}{n(n+1)(n+2)}\right) is equal to:EasySingle correct
  2. 3 Apr 2025, Shift 1 · Q7The sum 1+3+11+25+45+71+…1 + 3 + 11 + 25 + 45 + 71 + \ldots upto 20 terms, is equal toMediumSingle correct
  3. 4 Apr 2025, Shift 2 · Q5If the sum of the first 20 terms of the series…MediumSingle correct
  4. 5 Apr 2024, Shift 1 · Q6If 11+2+12+3+…+199+100=m\frac{1}{\sqrt1+\sqrt2}+\frac{1}{\sqrt2+\sqrt3}+\ldots+\frac{1}{\sqrt{99}+\sqrt{100}}=m and…EasySingle correct
  5. 9 Apr 2024, Shift 2 · Q24If…HardNumerical value
  6. 30 Jan 2024, Shift 1 · Q24Let α=12+42+82+132+192+262+…\alpha=1^2+4^2+8^2+13^2+19^2+26^2+\ldots upto 10 terms and β=∑n=110n4\beta=\sum_{n=1}^{10}n^4. If 4α−β=55k+404\alpha-\beta=55k+40, then kk is equal…MediumNumerical value
  7. 31 Jan 2024, Shift 1 · Q5The sum of the series 11−3⋅12+14+21−3⋅22+24+31−3⋅32+34+…\frac{1}{1-3\cdot1^2+1^4}+\frac{2}{1-3\cdot2^2+2^4}+\frac{3}{1-3\cdot3^2+3^4}+\ldots up to 10-terms isMediumSingle correct
  8. 6 Apr 2023, Shift 1 · Q7The sum of the first 20 terms of the series 5+11+19+29+41+…5+11+19+29+41+\ldots isMediumSingle 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.