JEE Main 2020MathematicsProbabilityMediumNumerical

JEE Main 2020 — Probability Question with Solution

JEE Main 2020 (05 Sep Shift 2)

Question

In a bombing attack, there is 50% chance that a bomb will hit the target. At least two independent hits are required to destroy the target completely. Then the minimum number of bombs, that must be dropped to ensure that there is at least 99% chance of completely destroying the target, is .....

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Show full solutionCorrect answer: 11
Correct answer
11

Step-by-step explanation

let probability of hitting the target =p⇒p=12

Let n be the minimum number of bombs

According to given condition
1-C0nP0(1-P)n+C1nP1(1-P)n-1≥99100

⇒  2n≥(n+1)100

n=10⇒210≥1100 Reject n=11⇒211≥1200 Select 

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About this question

This is a previous-year question from JEE Main 2020, 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.