Well i just recently finished reading HP and the Order of The Phoenix and i was thinking one day that J.K stuffed up.

Now in the book the sorting hat says that Slytherin takes only pure bloods, Gryffindor takes the brave and courageous Ravenclaw takes the keenest of minds and Hufflepuff takes the rest.

SPOILERS AHEAD
If you haven't read the book Orderof the Phoenix etc do not continue reading.




BUT my query is that when the sorting hat first puts Harry in Gryffindor it also says that he would do well in Slytherin because he has the connection with Voldermont but Harry is half blood wizard yes both his parents are magic but his mother's parents aren't magic making him half blood which brings me to my next point later in the series it also states Tom(Voldemort) is half blood as well but he was alicated to Slytherin so unless they were exceptions why was Tom in Slytherin and why would the sorting hat consider putting him in that house as well if they were both half blood not pure.