A cake is cut so that, one piece which is half of the cake, is twice as largest as the other piece. How many pieces are there?

One piece is half of cake 1/2
Above mentioned piece is twice larger the next piece 1/4
1-[1/2+1/4]
1-3/4=1/4
One Piece is 1/2
Second Piece is 1/4
Third Piece is 1/4