As a variant of problem 35, do the following:

(1) Construct a counterexample for the statement
   (A n B) u C = A n (B u C)   *if*  A subset C

(2) Construct a counterexample for the statement
   (A n B) u C = A n (B u C)   *only if*  A subset C

(3) Prove: 
   (A n B) u C = A n (B u C)   *if and only if*  C subset A


(Note: for here, I have used the letters n and u to denote intersection 
and union respectively)