what is the probability of getting 7 or 11 when a pair of dice are tossed

n(S)=(6)^2=36
S={(1,1),(1,2),(1,3),(1,4),(1,5),(1,6),(2,1),(2,2),(2,3),(2,4),(2,5),(2,6),(3,1),(3,2),(3,3),(3,4),(3,5),(3,6),(4,1),(4,2),(4,3),(4,4),(4,5),(4,6),(5,1),(5,2),(5,3),(5,4),(5,5),(5,6),(6,1),(6,2),(6,3),(6,4),(6,5),(6,6)}
A={getting 7}
B={getting 11}
A,B are mutual exclusive events →A∩B=∅
A={(1,6),(2,5),(3,4),(4,3),(5,2),(6,1)}    n(A)=6
B={(5,6),(6,5)}      n(B)=2
P(A)=(n(A))/(n(S))=6/36=1/6   
P(B)=(n(B))/(n(S))=2/36=1/18
P(A∩B)=0
P(A∪B)=P(A)+P(B)-P(A∩B)=6/36+2/36-0=8/36