# Fishtank Riddle

• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

Theres a rectangular fish tank inmy room.
Fish tank can hold up to 100 litres of water.
In the same room, theres a 3.75-litre round bucket and a tap (with hose)

1) Fishtank is then filled with water to the brim.

2) now i wanna the fishtank to be exactly half filled with water.

how do i do that? to make fishtank to be exactly half....
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

PM
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

I have changed the figures in the question. lol
and also, you can't take 2 litres using a 3 iltres bucket. Coz you dont have a measuring tool....
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

Well the answer is the same as the fist version, just different numbers.

Has anyone actually done the water puzzle from die hard, because they show the end of it, but not the actual process. I did it once but I can't remember the puzzle or the solution lol
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

the answer and method is not the same
coz you cant use the bucket to estimate a a redcution of 2 litres.

its a 3.75 litres bucket and you havent got any tool to measure the capacity..
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

hint: I can change the capacity of bucket and tank to be anything I want

but

the method of getting tank half filled with water is......
one way (as far as I know)....lol
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

So the actual problem is:

bucket of volume x
bath of volume y
obtain 0.5y in the bath

where y > x > 0

And conceivably x and y can be any real number > 0 , so 3.5463353 and 217.11313125 would be valid?

Is that more accurate to the problem? If so, I'm buggered if I know the answer......

Can I have a marker pen?
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

lol.
hint: answer is logical
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

can I have a marker pen?
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

lol
no marker pen for you!
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

grrrrrrr

damn you!

A spirit level?
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

lol why do you need a marker pen?
using yr brains makes it more fun, more challenging... lol
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

Well I could combine the marker with the hose to make a compass (just trust me on that) and then I coul treat the top and bottom of the bath as lines, and then use construction to find the line exactly halfway between them, mark that line and then fill up to there.

Although I worked out an easier way
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

yep yep , i see what u mean.
lol
no marker, no measurement tool...
that will make the whole thing easier..
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

I sussed an answer and even drew little pictures to go with it I've PM'd it to ya a little while back. Pick up your PM's biatch!
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

lol.
any takers???
• Novice
• Posts: 23
• Loc: Hilo, Hawaii

3+ Months Ago

I give up! I've been sitting here for well over an hour with a calculator in my hand driving myself nuts on this one. I know the answer is probably really simple but I can't for the life of me figure it out right now. Maybe tomorrow my head will be a little clearer if nobody else has figured it out by then.
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

lol it's a good one ain't it.

Take a look back at the other posts, you can do it numerically with a couple of eg's, but you any size bath and bucket, you can't do it numerically or algebraically.

This was the problem I had, I saw numbers and thought maths. But it's a logically solution to a logic problem. It's a nice simple answer, as always with these.

Good luck

//edit, I just tried to google it, but I can't seem to find the answer that way, so there's no point in trying to cheat (you know who you are)!
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

Quote:
Maybe tomorrow my head will be a little clearer if nobody else has figured it out by then.

lol. nice avatar
I can see thru yr head!!!!
• Expert
• Posts: 588

3+ Months Ago

can you measure the time it took to fill up the fish tank?
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

Is there a stopwatch in the puzzle?
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

heheh. no time limit.
• Proficient
• Posts: 298
• Loc: Brooklyn Transplanted into NJ

3+ Months Ago

Can we start with the tank empty? I can do it with the tank empty but not full hehe.

Dangles
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

Go on, whats your answer, but remember that the puzzle is also supposed to cover any size bucket and any size bath.
• Proficient
• Posts: 298
• Loc: Brooklyn Transplanted into NJ

3+ Months Ago

Ok here goes

Tank is empty but can hold 100 litres

using the 3.75 bucket 26 times into the tank will give you 97.50 litres

On the next filling that will leave exactly 1.25 litres in the bucket.

Now tip the tank back to empty again and pour the 1.25 into the tank and then an addition 13 times, and that will be exactly 50 litres.

D
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

That was my first solution, but there is one that works no matter the sizes of the bucket and the bath
• Proficient
• Posts: 298
• Loc: Brooklyn Transplanted into NJ

3+ Months Ago

Hmm really. And it doenst involve a tape measure and glass cutting drill bit??

Ok back to the drawing board.

D
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

Just the stuff thats in the room
• a.k.a. dM
• Posts: 5146
• Loc: SC-USA

3+ Months Ago

It doesn't matter how big the bucket, or fishtank is...

Keep removing water until you can tilt the fish tank and create a straight line with the surface of the water between the top corner and it's opposing bottom corner.

• Genius
• Posts: 5735
• Loc: Sub-level 28

3+ Months Ago

Btw, the Die Hard one... 3 gallon bottle, 5 gallon bottle, get 4 gallons in the 5 gallon bottle... easy..

Fill the 3 gallon with water, and pour it into the 5 gallon. Leaves 2 gallons of space.

Fill up the 3 gallon, pour it into the 5 gallon til it's full. Leaves 1 gallon left in the 3 gallon bottle.

Empty the 5 gallon, and pour the 1 gallon from the 3 into the 5.

Fill up the 3 gallon, pour it into the 5, there's 4 gal in the 5 gal bottle.
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

you could have managed a better picture than that dm! This was my effort lol:

I used the bucket as support in case the tank was too heavy filled with water

Also for some reason I thought it was a bath all along. I have no idea why
• Genius
• Posts: 5735
• Loc: Sub-level 28

3+ Months Ago

Or...

Fill up the 5, pour into the 3 til it's full. Leaves 2 gallons in the 5 gal.

Empty the 3, and pour the remaining 2 gallons from the 5 into the 3.

Fill up the 5, pour into the 3 (remember there's 2g already in it), so that knocks off a gal and there's 4 left in the 5 gal.
• Genius
• Posts: 5735
• Loc: Sub-level 28

3+ Months Ago

Btw, 100 liters of water is gonna weigh about 220lbs, so it's gonna be kinda difficult to lift it any place, with a foot wedge or not
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

nice solution to the question that <b>wasn't</b> asked axe
• Genius
• Posts: 5735
• Loc: Sub-level 28

3+ Months Ago

You mean this question that wasn't asked by you?

rtm223 wrote:
Has anyone actually done the water puzzle from die hard, because they show the end of it, but not the actual process. I did it once but I can't remember the puzzle or the solution lol
• a.k.a. dM
• Posts: 5146
• Loc: SC-USA

3+ Months Ago

rtm223 wrote:
you could have managed a better picture than that dm!

LOL!!! Ok, granted.

Let's see, that's 1 demerit for a weak effort, and two merits for the correct answer, aye?
• Mastermind
• Posts: 1855
• Loc: Uk

3+ Months Ago

@dm

Axe wrote:
Btw, 100 liters of water is gonna weigh about 220lbs, so it's gonna be kinda difficult to lift it any place, with a foot wedge or not

Well it's 50 litres, because I syphened out most of the water with the hose, then proped up the bath, then used the hose to fill up the rest hehehe

//edit, ok I did ask that question, but but but.... ah heck!
• Guru
• Posts: 1214
• Loc: Somewhere on Google Earth

3+ Months Ago

OR OR OR

lift the tank, then throw it out a window

now the tank has a volume of 0

0/2 = 0

the tank is half full
• Posts: 221
• Loc: Corpus Christi, TX

3+ Months Ago

measure the tank (how tall it is)

then split that measurement in half

remeasure it and make a mark

then just fill the tank up or empty it down till it is half empty/half full

thats alot easier than just trying to figure out how many buckets to use...
• Expert
• Posts: 588

3+ Months Ago

yeah but they said you had no measuring devices. I'm glad someone figured it out.
• Mastermind
• Posts: 2115
• Loc: australia

3+ Months Ago

Quote:
Btw, 100 liters of water is gonna weigh about 220lbs, so it's gonna be kinda difficult to lift it any place, with a foot wedge or not

we can change it to 25 litres capacity for fishtank if you want. lol
glad somebody got it right !

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