[tex]P\left( E \right) =\frac { 1 }{ 2 } \times \frac { 1 }{ 2 } \times \frac { 1 }{ 2 } =\frac { 1 }{ 8 } [/tex]
You could get this answer by creating a tree diagram or by thinking about the possibilities that exist.
Realm of possibilities with one toss:
H or T.
Realm of possibilities with two tosses:
H, H
H, T
T, H
T, T
Realm of possibilities with three tosses:
H, H, H
H, H, T <--- 1/8 chance of taking place
H, T, T
T, T, T
T, T, H
T, H, H
T, H, T
H, T, H
