Answer:
a) 1/4
b) 3/4
c) 1/4
Explanation:
Possible outcomes of two tosses of a coin:
HH
HT
TH
TT
There is a total of 4 possible outcomes.
p(event) = (number of desired outcomes)/(total number of possible outcomes)
a) 2 heads
HH <------- 1 desired outcome
HT
TH
TT
p(2 heads) = 1/4
b) at least 1 head
HH \
HT } <------ 3 desired outcomes
TH /
TT
p(at least 1 head) = 3/4
c) no heads
HH
HT
TH
TT <------- 1 desired outcome
p(no heads) = 1/4