“I don’t understand it” said Jessica. “Why would you want to do that?”
“It’s a puzzle” replied Colin. “Look, let me get some props.”
It was early morning and Colin was attempting to teach Jessica and Roger a logic puzzle. He rummaged around and pulled out an apple and a carrot.
“So you have a boat and it can only carry two things at once. You have Roger, who’s hungry, an apple and a carrot.”
“I like the sound of this still” replied Roger. “And now I can see the goodies too!”
“Shh Roger” said Colin. “You can also be in the boat and you need to get all three things across the lake. Every trip you make must have at least one of the things in the boat with you. How do you do it without Roger eating the apple or the carrot?”
Jessica looked at Colin, at Roger, at the carrot and then back at Colin.
“I don’t know!” she said. “This is hard!!”
“We could go down the lake and try this for real” said Roger. “I know there’s a boat down there – and it is a nice day. We could even have the apple and carrot for lunch!”
Colin thought that was a lovely idea, so they set off.
“Oh dear” said Jessica. “I don’t know how to swim and I’m worried I’ll fall out of the boat”.
“No matter” replied Colin “you can wear this and it will help you float; I’ll also teach you how to swim later in the year.”
“So” said Colin “to the matter in hand. How will you get the carrot, apple and Roger across the lake?”
Roger looked at the carrot. It had been ages since breakfast. He was hungry and looking at Jessica who was thinking hard he worried it would be ages until lunch as well. What to do…
“ROGER!!” cried Colin. But it was too late. In one swift gulp, the carrot was gone. Yum!
“Well I can solve the problem now” said Jessica. “I put Roger and the apple in the boat and we go across!”
“Not the answer I was looking for” replied Colin, “but it would seem Roger has helped you out. For that, you can have the apple. Roger – you get to wash up the dinner plates for a week!”
“But we solved the problem though” said Roger. “That must count for something!”
So how would you solve the puzzle? I’ve put the answer below….
First, Colin rows across the lake with Roger and the apple.
Colin then rows back with just the apple (Roger is now on the other side)
Finally, Colin rows back with the apple and the carrot. Everybody is now across the lake!