Question 316832
a) Look at the 2 possible outcomes. 
H 
T
P(H)=1/2
.
.
b) Look at the 2 possible outcomes. 
H H 
H T
P(T)=1/2
.
.
c)Look at the 4 possible outcomes. 
H H
H T
T H 
T T
P(T,T)=1/4
.
.
d)Look at the 4 possible outcomes. 
H H
H T
T H 
T T
P(T,H)=1/4
.
.
e) From d) P(T,H)=1/4
P(H,T)=1/4
P(T,H or H,T)=1/4+1/4=1/2
.
.
f) 
P(at least one head)+P(all tails)=1
P(at least one head)=1-P(T,T)
P(at least one head)=1-1/4
P(at least one head)=3/4