# How many people know hex if only you and dead people know hex?

How many people know hex if only you and dead people know hex?

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marcus
Gold Member
Dearly Missed
Tom McCurdy said:
How many people know hex if only you and dead people know hex?

57006, in decimal notation,
or DEAE, in hex

marcus
Gold Member
Dearly Missed
that is a good riddle, Tom McCurdy
BTW there are other developments besides string
happening in quantum gravity, maybe your
summerschool in the UK will introduce you to those as well
there is a quantum gravity conference in London at
Imperial College on Sept 6 and 7

a 5 literd bottle, a 7 litered bottle and a tank, how can i get 4 lits of water in the end if I start by pouring water from the tank into the 5 liter bottle first ?

Last edited:
5 literd bottle, a 7 litered bottle and a tank, how can i get 4 lits of water in the end if I start by pouring water from the tank into the 5 liter bottle first ?

1) Pour the 5 L into the 7 L bottle.
2) Fill the 4 L.
3) Pour the 4 L into the 7 L (with 2 L left in the 4 L).
4) Pour the remaining 2 L in the 4 L bottle into the tank.

5) Empty the two bottles and repeat from step 1 to get the last 2 L.

?????????????????????????????? :sm: ??????????????????????????????
I am sorry, I think I made mistake, I didn't clearify what I meant....
I have only 2 empty bottles, one 5, one 7 and a tank/water container.
I will go fill 5 L bottle first, and I am only allowed to use 3 of them to finally getting 4 L of water. How will I go ???? :sm:

By the way, your avatar is really kewl, I would also like to have one for myself..:sm:

Integral
Staff Emeritus
Gold Member
Assuming that the tank is empty and that is where you want the 4l. pour the 5l into the 7l, fill up the 7l, use the 7 to fill the 5, pour 2l into tank. Empty the 5 into the 7, fill the 7, fill the 5, pour 2l into the tank, which now has 4l.

But what if I am only allowed to used 5 or 7 as a place to store 4 lits ? How can i make it then ?

AKG
Homework Helper
Pattielli said:
a 5 literd bottle, a 7 litered bottle and a tank, how can i get 4 lits of water in the end if I start by pouring water from the tank into the 5 liter bottle first ?
I assume the tank has an endless supply of water?

1. Fill the 5L bottle (as required)
2. Empty the 5L bottle.
3. Fill the 7L bottle.
4. Pour 5L of the 7L into the 5L bottle, filling it, leaving 2L in the 7L bottle.
5. Empty the 5L bottle.
6. Pour the 2L in the 7L bottle into the 5L bottle.
7. Fill the 7L bottle.
8. Pour 3L from the 7L bottle into the 5L bottle, filling it, leavint 4L in the 7L bottle.

Done.

:sm: :sm:
I actually can go from 7 but i don't knbow how to go from 5, thats why i made this question...

:sm:
Okay, you now have any riddle ?

Gokul43201
Staff Emeritus
Gold Member
If you really want to use the 5L to start, you can do that too.

1. Pour 5L in 7L bottle.
2. Fill 5L bottle again, and pour 2L into 7L bottle to fill it.
3. Empty 7L bottle and pour the remaining 3L into it.
4. Fill 5L bottle and pour 4L into 7L bottle to fill it.
5. Empty 7L bottle and pour the remaining 1L into it.
6. Fill 5L bottle and pour it all into the 7L bottle.
7. Again fill 5L bottle and pour 1L into 7L bottle to fill it.

You now have 4L in the 5L bottle.

This is the same as finding a solution to the congruence problem :
5n==4 (mod 7), and clearly, n = 5 is a solution, meaning that 5 fills of the 5L bottle gets you there.

Yep, thats really kewl, you are really great ! :sm:

marcus said:
that is a good riddle, Tom McCurdy