I found an amazing glitch in the shopkeeper's quiz: if you click on the last item of a recipe thrice, it counts as two correct answers tried it over and over again. This way I finish the whole quiz easily.
PS: if u try to do it three times the last item becomes permanent factor in the next question. So unless u have a very common item as your last item, like the recipe, your quiz ends
I hope DOTA 2 admin sees to my thread or post whatever, and tries solving this cheat issue.