Equal sets: Two sets A and B are said to be equal if every element of A is a member of B and every element of B is a member of A.
P = {C,A,T,A,R,A,C,T} = {C,A,T, R}
Q = {T,R,A,C}
Here, every element of A is a member of B and every element of B is a member of A.
Hence, P = Q