You could get the goldDiscrete Mathematics Level pending
Ollivander has received a stock of wands for the new session . He has to arrange them and put on the rack . There are 6 types of cores for the wands i.e phoenix feather, dragon heartstring, Veela hair, unicorn hair, Thestral tail hair, Kneazle whiskers and he has a sudden whim that he won't put phoenix feather and dragon heartstring together . Find the total number of ways .