Bob is quiet. Bob is smart. Bob is young. Charlie is red. Charlie is rough. Charlie is smart. Charlie is white. Charlie is young. Dave is rough. Dave is white. Fiona is quiet. All cold, white things are young. If something is rough then it is red. If something is smart then it is cold. All quiet things are smart. If something is red and white then it is quiet. If something is rough and not red then it is white. If something is quiet and not white then it is young. If something is not young then it is cold.
Dave is not smart.