JEE Main 2020 — Probability Question with Solution
From: JEE Main 2020 (Online) 9th January Morning Slot
Question
In a box, there are 20 cards, out of which 10
are lebelled as A and the remaining 10 are
labelled as B. Cards are drawn at random, one
after the other and with replacement, till a
second A-card is obtained. The probability that
the second A-card appears before the third
B-card is :
Choose an option
Show full solutionCorrect option: B
Correct answer
B
Step-by-step explanation
Possibilities that the second A card appears before the third B card are
=AA + ABA + BAA + ABBA + BBAA + BABA
= + + + + +
= + + + + +
=
=AA + ABA + BAA + ABBA + BBAA + BABA
= + + + + +
= + + + + +
=
Practice this on the real CBT interface
Solve this JEE Main question (and the rest of the Probability chapter) on PrepSharp's TCS iON-style CBT player — with timer, bookmarks and session analytics.
Solve interactively →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.