My eight favorite riddles (v. difficult) - Page 3

if it displaces more volume in the boat than out of the boat, why would the water level fall? following your logic I thought it'd rise

brick is heavier/more dense than water. so whilst in the boat, it displaces the volume of water equal to that of the weight of the brick. when the brick is thrown in, the volume of the brick is displaced. so water level fall :D

Spoiler chain.

Ask yourself this; What happens when you get into a bathtub that is nearly full, but not quite going over the edge?

Or, think of a ball that weighs fifty pounds, but is as golf-ball sized. It's not moving much water in it's space, no matter how much it weighs.It's pushing some water up, but not a whole lot. Now, imagine putting that fifty pound ball on a boat, which has a much wider surface area. More water gets pushed up, because of that weight being spread out across more of the water.

Ok this is pretty simple - The brick displaces more water by displacing weight in the boat than displacing volume in the lake. Therefore the water level actually should drop a little when you throw the brick into the lake. Of course it's a LAKE so I doubt it makes any difference at all. Maybe if you were in a boat in a small tub. Lol.

That's the only one I can do, cause it's pretty simple physics. But the other would probably take me ages to figure out.

. You ask the watch if the next time it flashes the colour will be blue. If the watch flashes the blue light you know blue is true. If you get the yellow light, you know yellow is false.

Hmm this seems very wierd but i cant see what is wrong.
You ask the watch:
If I ask you if there is a horse behind both door 1 and 2, will you then show blue?
Then it can show blue or yellow.
When you ask later if there is a horse behind both those doors it can show blue, and then blue will be yes wich means the car is in door 3. If the watch shows yellow, then it means that blue is NO and that means yellow must be yes, wich means there are 2 horses in those doors aswell and the car is once again in door 3.
It quite clear, but i can't understand it, coz then it means the car is always in door 3. And if u ask about door 2 and 3 then its always in door 1, so you can choose where its gonna be!!

Never mind, I found out what was wrong. If the watch shows yellow the first time, and yellow means no. Then it will show yellow when i ask the second question and the car can be in nr1 OR nr2 so u dont know for sure.. but im getting somewhere i can feel it^^

You make 4 groups of 3 marbles.
you weigh 2 groups.
a) The scale tilts
b) The scale does not tilt

a) take the hevier 3 marbles and weigh them with 3 you haven't weighted.
a1) tilts again -> You know in which pack of 3 the marble is and you know it's hevier.
Take the 3 marbles weigh 2 -> does'n tilt it's the last one
tilts -> take the hevier one
a2) doesn't tilt -> You know in which pack of 3 the marble is and you know it's lighter.
Take the 3 marbles weigh 2 -> does'n tilt it's the last one
tilts -> take the ligher one

b) take 3 of the marbles you havn't weighted and weigh them with 3 or the marbles you have
b1) it tilts -> you know in which pack of 3 the marble is and if it's lighter or hevier
Do like a1 or a2
b2) It doesn't tilt... -> You know in which pac of 3 the marble is but have no clue if it's hevier or lighter... And I'm stuck ;D

Only 82.5% solved :p

there are 10 cheating men in the town.

if there is only 1 cheating man, then he will be kicked out the first night. the reason is that his wife knows that someone in the town is cheating, but she knows that no one else in the town is cheating, so it must be her husband.

if there is two cheating men, then the they will be both kicked out on day 2. the reason is that their wives know that one other husband is cheating, but he was not kicked out on the first night so they deduce that that wife must know the same thing.

and on and on until the 10th day or 10 men

Yea. It's just a comparison of densities, right? If you have something denser than water in the boat, the water level will fall when you put it in the water. For example, if the boat was half filled with water, when you bailed all the water out, the water level would be the same. If you had something lighter than water, it takes up more volume than equally-weighing-water, so the water level would rise (except stuff lighter than water floats so you'd have to magically suspend it there somehow)

Messed up... need to yhink again