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(#M40003302) GATE Numerical Ability question QUANTITATIVE APTITUDE Keep an EYE

A coin is tossed 4 times. What is the probability of getting heads exactly 3 times?

Asked In Gate CHANDAN KR SINGH (13 years ago)

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Dr.Dipin Singh  (13 years ago)

Two possible combinations are
HHTH,HTHH, HHHT and THHH.

Probability of each case = 1/2*1/2*1/2*1/2= 1/16

the probability of getting heads exactly 3 times= 4*1/16+ =1/4

Is this solution Helpfull? Yes (14) | No (3)  

Rajib Paul  (13 years ago)

16 combination is possible.
4 ways to get 3 head,
so 4/16=1/4:)

Is this solution Helpfull? Yes (6) | No (1)  

Swetha.R  (13 years ago)

3/16(possibility of occuring events/Total number possibility of events)



16=2^n=2^4

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Rahul kumar singh  (12 years ago)

So, my outcome should contain 2 heads and 2 tails. Total no of ways in which 2 heads and 2 tails can be arranged is=no of arrangements of 4 things taken all at a time where 2 are alike of one kind and 2 are alike of the other kind= 4!/(2!*2!)
=6 .Now total no of possible outcomes=2^4=16 Therefore required probability= 6/16
=3/8

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shwetha  (7 years ago)

the total no of outcomes is 2^4=16.out of this only 4 has exactly 3 heads .so 4/16=1/4

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