Question

A coin is tossed 2 times what is the probability of getting one head atmost one head

Answer 1

Ok..given , a coin is tossed 2 times . therefore . sample space = 

{HH  HT  TH  TT}

now first u need to understand the meaning of atmost. 

At most one head : 1 head is ok and none head is also ok , but more than 1 head are not applicable.

therefore probability of getting atmost 1 head = 3/4  [HT  TH  TT}

Answer 2

total outcomes,n= (T,T),(H,H),(T,H),(H,T)=4
favourable cases for getting one head,m1=(T,H),(H,T)=2
probability of getting one head,P(E1)
=m1/n
=2/4
=1/2
favourable cases for getting atmost one head,m2=(T,T),(H,T),(T,H)=3
probability of getting atmost one head,P(E2)=m2/n
=3/4