Okay, you will not find most of these past questions (if not all) by searching with their names on Okadabooks. This doesn’t mean they were hidden from users intentionally; you just won’t get any results when “waec” is searched for. In this post (or image above) i’ve managed to show us how to search for almost all the past questions with one word! Okadabooks. Of course, you have to be signed in to do this. You can get them all for free over there.
If you don’t want to go through the stress of searching, see sample here.