Math riddles

[Qfwfq]

If the planks are too light he can always get a rock at least 9 times his own weight and put it on the outermost end.

[ughaibu]

If he has the first plank projecting just over a yard then bridges the remaining nine yards with the second plank, wouldn't the weight needed to balance him be approximately 5/8 of his weight? How much does his armour weigh? Maybe he could use that as a balance.

[ughaibu]

How about laying one plank on the other and rafting across, on the way back they have a plank each?
If I remember correctly, alligators dont bite under water, ten yards isn't too much to swim submerged.

[Rincewind]

If we assume the moat's bank is curved enough, you could place both ends of one plank on the same side of the moat so the middle of the plank is over the water. Then place the other plank perpendicular to the first from the middle of it to the other side.

Many assumptions about dimensions here.

[arkain101]

Well, first of all it doesnt say there is no bridge. So the knight should take a good walk around first to see if there is a bridge.

If all there is, is a 10 yard gap, and 2 planks 9 yards long, and no other rocks or tools or anything else but him and his two boards.

Then if the princess was on the other side lol, he could throw a board across and tell her to stick one yard and a bit of the board over the edge on her side, get her to stand on the far end. Then he could lay his board across and onto the overhanging end of the princesses board and walk across.
It seems there is a cruicial part of the puzzle missing. I used the princess because all it said is she was on the other side.

But Logically, this is a really tough one to answer. It would be too difficult to pole vault with a 9 yard plank.

but if he could jump a few yards and the planks were good in heavy he could place a board with 3 yards over hang on the other side and his with 4 yards of over hang on his side, and get a good running jump and hope to heck hes fast enough lol.

[Qfwfq]

What a downright dumb thing I said! 9 times his weight!!!!

At least 1/9 is enough! And the princess is a great alternative to the rock!

Originally Posted by Turtle

How about stacking the planks one on the other & floating across? Use the planks to club the gators senseless?:

The first had crossed my mind, but not the second!!!!!!

RW, try working out the geometry for that. I tried it for square corners and it doesn't work, the planks would need to be almost 9.5 feet, 9 ain't enough. I wouldn't trust those crocs underwater either.

[C1ay]

Originally Posted by mheavner

I have one...I don't know the answer so that's why I'm here. It's for my son's extra credit. We can't figure it out. Help?!? I typed it exactly as it is on his paper.
here goes...The knight needs to cross the moat which is 10 yards wide without getting eaten by the alligators. He looked around and found only 2 planks that were each 9 yards long. The knight has no way to fasten them together. How can the knight cross the moat and get to his princess?

It appears to me that the castle is in the center of the moat and it is 10 yards wide on all sides. My son also said the water is too deep to use them as stilts. The knight has no tools or anything like that.We thought we could overlap them but the boards will fall apart in the middle. Anyone have any suggestings??

Is the moat round or square? With a square moat you could lay one plank caddy-corner across one of the moat's corners and the other plank from the middle of the first plank to the other side of the moat.

[Qfwfq]

For that to work they would have to be more than 9.4281 ft long.

[TheBigDog]

If I am not mistaken, the knight weighs the same as a duck, and therefore he is made of wood. So he can float on the water, and the the alligators will not eat him since they are carnivores.

Sir Bedevir

[C1ay]

Originally Posted by Qfwfq

For that to work they would have to be more than 9.4281 ft long.

Yeah, I didn't actually work it out, just tossing the image around in my head.

The only other idea that comes to mind is using the two planks as skis