Question

A fair coin is tossed twice. Define the events.
A = Getting a head on the first toss.
B = Getting a head on the second toss.
A and B = Getting a head on both the first and second tosses.
A or B = Getting a head on the first toss, or the second toss, or both tosses.

(a) Find P(A) = the probability of A.
(b) Find P(B) = the probability of B.
(c) Using the multiplication rule, find P(A and B)
(d) Using the addition rule, find P(A or B).

I got:
a) 1/2
b) 1/2
c) 1/4
d) 1/8

Can someone please correct my answers and give me explanations on the ones I got wrong? Thank you!

Answer 1

Your first three answers are right.

I prefer to solve the last by saying that this outcome means
one minus getting tails both times

= 1-1/4 = 3/4

That's the answer, you need to use "addition rule."

Answer 2

Thank you very much! I appreciate your help :)