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  • In a box, there are 20 cards, out of which 10 are labelled 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

In a box, there are 20 cards, out of which 10 are labelled 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: 

Option: 1

\frac{15}{16}


Option: 2

\frac{9}{16}


Option: 3

\frac{13}{16}


Option: 4

\frac{11}{16}


Answers (1)

best_answer

 

-

AA + ABA + BAA + ABBA + BBAA + BABA

\frac{1}{4}+\frac{1}{8}+\frac{1}{8}+\frac{1}{16}+\frac{1}{16}+\frac{1}{16}=\frac{11}{16}

Correct Option (4)

Posted by

SANGALDEEP SINGH

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