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Saturday, 31 October

JEE Main 2022 · MathsNumerical answerNumerical valueMediumMulti-step

JEE Main 30 June 2022, Shift 1, Maths Q26

Question 26 of 90 in this shift, Maths question 26 of 30, Section B.

A hostel has 100 students. On a certain day (consider it day zero) it was found that two students are infected with some virus. Assume that the rate at which the virus spreads is directly proportional to the product of the number of infected students and the number of non-infected students. If the number of infected students on 4th4^{\mathrm{th}} day is 30, then number of infected students on 8th8^{\mathrm{th}} day will be __________.

Official answer

90

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. 26 Feb 2021, Shift 1 · Q65The rate of growth of bacteria in a culture is proportional to the number of bacteria present and the bacteria count is 1000 at initial…MediumSingle 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.