JEE Main 2026 — Probability Question with Solution
JEE Main 2026 (28 January Shift 1)
Question
A bag contains 10 balls out of which are red and () are black, where . If three balls are drawn at random without replacement and all of them are found to be black, then the probability that the bag contains 1 red and 9 black balls is:
Choose an option
Show full solutionCorrect option: A
Correct answer
A
Step-by-step explanation
Using Bayes' theorem:
where for each .
When : .
Calculating .
Numerator is .
So .
Therefore
where for each .
When : .
Calculating .
Numerator is .
So .
Therefore
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This is a previous-year question from JEE Main 2026, 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.