Generally, a "XX km/hr ends" sign means that the road reverts back to the default Ontario speed limit which is 80km/hr, or 50km/hr if you're in an urban area. I have no idea how you're supposed to determine which type of area you're in.
I like these two signs 200 meters from each other just outside of Calabogie: 40km/hr ends, followed immediately by 60km/hr ends. So the "40km/hr ends" means the limit is now 80. The second "60km/hr ends" sign means... the limit is still 80. Ok, sure?