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Saturday, 31 October

JEE Main 2021 · MathsMultiple choiceSingle correctMediumCalculation

JEE Main 26 February 2021, Shift 1, Maths Q65

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

The rate of growth of bacteria in a culture is proportional to the number of bacteria present and the bacteria count is 1000 at initial time t=0t=0. The number of bacteria is increased by 20% in 2 hours. If the population of bacteria is 2000 after klog⁡e(65)\frac{k}{\log_e\left(\frac{6}{5}\right)} hours, then (klog⁡e2)2\left(\frac{k}{\log_e 2}\right)^2 is equal to :
  1. (1)22
  2. (2)44Official answer
  3. (3)88
  4. (4)1616

Official answer

Option 2

NTA final key.

Chapter
Differential Equations
Topic
Variable Separable Form
Idea tested
Proportional Rate Problems

Same idea in other shifts

Asked 2× in all
  1. 30 Jun 2022, Shift 1 · Q26A hostel has 100 students. On a certain day (consider it day zero) it was found that two students are infected with some virus. Assume…MediumNumerical value

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.