Question

Four coins are tossed simultaneously what is the probability of getting (i) 2 heads (ii) 3 heads (iii) atleast 3 heads

Answer 1

Probability of getting 2 heads is 1 . 3heads is 3/2.atleast 3heads is also 3/2

Answer 2

Hi

If 4 coins are tossed total possible

outcomes are

HHHH , HHHT , HHTH , HHTT

HTHH , HTHT , HTTH , HTTT

THHH , THHT, THTH , THTT

TTHH , TTHT , TTTH , TTTT

Where H indicates head ,and

T a tail .

Number of total possible

outcomes = 16 ---( 1 )

i ) getting 2 heads :

Favorable outcomes = { HHTT,

HTHT , HTTH , THHT , THTH ,

TTHH }

Number of favourable

outcomes = 6 ---( 2 )

P( getting 2 heads ) = ( 2 )/( 1 )

= 6/16

=3/8

ii ) getting 3 heads :

Favorable outcomes = { HHHT ,

HHTH , HTHH , THHH }

Number of favourable

outcomes = 4 ---( 3 )

P( getting 3 heads ) = ( 3 )/( 1 )

= 4/16

= 1/4

iii ) getting at least 3 heads :

Favourable outcomes = { HHHH ,

HHHT , HHTH , HTHH, THHH }

Number of favourable

outcomes = 5 ---( 4 )

P( at least 3 heads ) = ( 4 )/( 1 )

= 5/16

I hope this helps you.

: )