A zookeeper is evacuating a zoo from a rampant flood – she has 2 animals in tow, and a bag of sloth feed.
To escape, they must cross a raging river. There is a boat, but it can only carry the keeper and one other thing.
One of the animals is a vicious bear! It’s hungry, too, but he knows his keeper well so won’t eat her, but he’s been eyeing up the sloth – he wouldn’t eat the feed.
The second is a sloth, clearly unable to cross the river alone.
The third item is the bag of sloth feed and the sloth is also hungry!
The keeper needs to get across with all three intact; the bear, sloth and feed.
How can she manage it without anything getting eaten?!
First of all, the zookeeper takes the vulnerable sloth across in the boat. She can’t leave the bear with the sloth, or else the sloth will be eaten.
She goes back and picks up the bear and brings him towards the sloth, but then picks the sloth up at the same time and takes him back with her to prevent him from being eaten.
Once she returns with the sloth, she drops him off alone and grabs the feed. She takes the feed over to the bear.
Finally, she returns once to collect the sloth.
Job done!