JEE Main 2018MathematicsProbabilityMediumMCQ

JEE Main 2018 — Probability Question with Solution

JEE Main 2018 (15 Apr)

Question

A box A contains 2 white, 3 red and 2 black balls. Another box B contains 4 white, 2 red and 3 black balls. If two balls are drawn at random, without replacement from a randomly, selected box and one ball turns out to be white while the other ball turns out to be red, then the probability that both balls are drawn from box B is :

Choose an option

Show full solutionCorrect option: C
Correct answer
C716 

Step-by-step explanation

Probability that box A is selected PA=12

Probability that box B is selected PB=12 

Let E be the event that one ball is white while the other is red.

∴ PE=PA·PE/A+PB·PE/B

=122·37C2+4·29C2=12621+836=1227+29=1663

Thus, PB/E=PB PE/BPE=191663=716

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About this question

This is a previous-year question from JEE Main 2018, 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.