Latest TCS Aptitude Question SOLUTION: a drawer holds 4 red hats n 4 blue hats. what is the probability of getting exactly 3 red hats or exactly 3 blue hats when taking out 4 hats randomnly out of the drawer n immediatl

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(#M40010793) TCS Numerical Ability question Keep an EYE

a drawer holds 4 red hats n 4 blue hats. what is the probability of getting exactly 3 red hats or exactly 3 blue hats when taking out 4 hats randomnly out of the drawer n immediatly returning evry hat to the drawer b4 taking out the next!??

1/2
1/8
1/4
3/8

Asked In TCS (11 years ago)

Unsolved Read Solution (5)

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PARAG KAMRA  (11 years ago)

suppose there are 4 red balls r1,r2,r3 and r4 and there are 4 blue balls b1,b2,b3 and b4
so total arrangements are 16
now if we take only 3 red balls and 1 blue balls,then there are total 4 arrangements
and same for in case of blue here are total 4 arrangements,so total are 8 arrangements
probability of getting exactly 3 red hats or exactly 3 blue hats when taking out 4 hats randomnly out of the drawer n immediatly returning evry hat to the drawer b4 taking out the next is 8/16=1/2(ans)

Is this solution Helpfull? Yes (19) | No (4)  

PARAG KAMRA  (11 years ago)

The order is also important here. RRRB or BBBR.
RRRB has 4 possible arrangements and BBBR too. So a total of 8 arrangements. For each of these arrangements p=1/16 so
Ans = 8/16 = 1/2

Is this solution Helpfull? Yes (3) | No (4)  

swetha  (9 years ago)

(4c1/8c1)*(4c1/8c1)*(4c1/8c1)*(8c1/8c1)
=1/8

Is this solution Helpfull? Yes (3) | No (2)  

Rishi Singh  (11 years ago)

(r,r,r,b)+(r,b,r,r)+(r,r,b,,r)+(b,r,r,r,)
hence 4/8 is ans
=1/2

Is this solution Helpfull? Yes (2) | No (7)  

ASWARTHA  (11 years ago)

1/2 is ans

Is this solution Helpfull? Yes (1) | No (9)  

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