JEE Main 2021 — Probability Question with Solution
From: JEE Main 2021 (Online) 31st August Morning Shift
Question
An electric instrument consists of two units. Each unit must function independently for the instrument to operate. The probability that the first unit functions is 0.9 and that of the second unit is 0.8. The instrument is switched on and it fails to operate. If the probability that only the first unit failed and second unit is functioning is p, then 98 p is equal to _____________.
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Show full solutionCorrect answer: 28
Correct answer
28
Step-by-step explanation
I1 = first unit is functioning
I2 = second unit is functioning
P(I1) = 0.9, P(I2) = 0.8
P() = 0.1, P() = 0.2
I2 = second unit is functioning
P(I1) = 0.9, P(I2) = 0.8
P() = 0.1, P() = 0.2
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This is a previous-year question from JEE Main 2021, covering the Probability chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.