Answer
E or H = {2, 3, 4, 5, 6, 7}
By counting:
$P(E or H)=\frac{6}{12}=0.5$
Using the General Addition Rule:
$P(E or H)=\frac{6}{12}=0.5$
Work Step by Step
S = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}. So, $N(S)=12$.
E = {2, 3, 4, 5, 6, 7}. So, $N(E)=6$.
H = {2, 3, 4}. So, $N(H)=3$.
E or H = {2, 3, 4, 5, 6, 7}. So, $N(E or H)=6$.
E and H = {2, 3, 4}. So, $N(E and H)=3$
By counting:
$P(E or H)=\frac{N(E or H)}{N(S)}=\frac{6}{12}=0.5$.
Using the General Addition Rule:
$P(E or H)=P(E)+P(H)-P(E and H)=\frac{N(E)}{N(S)}+\frac{N(H)}{N(S)}-\frac{N(E and H)}{N(S)}=\frac{6}{12}+\frac{3}{12}-\frac{3}{12}=\frac{6}{12}=0.5.$
