Question

Three different coins are tossed together. Find the probability of getting (i) at least two heads. (ii) at most two heads

Answer 1

Given :-

Three coins are tossed together

To find :-

• p(getting at least two heads)
• p(getting at most two heads)

Solution :-

When three coins are tossed,

Sample space =

{ (H,H,H) , (H,H,T) , (H,T,T) , (T,T,T) , (T,T,H) , (T,H,H), (H,T,H) , (T,H,T) }

__________________________

(i) P(getting at least two heads) = 4/8 = 1/2

--> (H,H,H) , (H,H,T) , (T,H,H) , (H,T,H)

__________________________

(i) P(getting at most two heads) = 3/8

--> (H,H,T) , (T,H,H), (H,T,H)

Answer 2

Given :-

Three coins are tossed together

To find out :-

(i)getting at least two heads.......n(E1)

(ii)getting at most two heads.......n(E2)

Solution :-

When three coins are tossed,

Sample space =

(H,H,H) , (H,H,T) , (H,T,T) , (T,T,T) , (T,T,H) , (T,H,H), (H,T,H) , (T,H,T)

n(s)=8

(i)p(E1)=n(E1)/n(s) =>4/8 => 1/2

(ii) P( E2)=n(E2)/n(s)=>3/8