candidate keys for above relations are - A,C,E
Super key is a superset of candidate key. now considering each candidate calculate super key
no of super keys wih A(B,C,D,E)= $2^4$ (every attribute has 2 choices either i can be in superset or not)
no of super keys wih C(A,B,D,E)= $2^4$
no of super keys wih E(A,B,C,D)= $2^4$
no of super keys wih {A and C}(B,D,E)= $2^3$
no of super keys wih {C ad E}(A,B,D)= $2^3$
no of super keys wih {A and E}(B,C,D)= $2^3$
no of super keys wih {A and C and E}(B,D)= $2^2$
total number of superkeys = no of superkey (A U C U E)
= $2^4$ + $2^4$ + $2^4$ - $2^3$ - $2^3$ - $2^3$ + $2^2$
= 28
please correct me if i'm wrong