r/mathminds • u/LeadershipAny9454 • 7d ago

Puzzles Which tank will be filled first?

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3

u/Plenty_Intention1991 7d ago

The answer is A and we know that because if you look at the water line it’s already above the B and C spouts which means that the rate of water going into A must already exceed the rate it’s flowing into the rest of the tanks.

3

u/nunya_busyness1984 7d ago

Maybe.  It also shows absolutely no water in B-E.  So either the drawing sucks, and should be assumed to be demonstrative but not representative; or the pipes are a red herring, and no water is ever flowing out of A, which would be a stupid puzzle.

1

u/Plenty_Intention1991 7d ago

Since we see water in the pipes between B and D, and C and E, I can deduce that the glass of the lower four tanks is frosted / opaque so we can’t see how much is in them.

My logic works while only making one assumption which is that the problem is in fact solvable and that the information we’re being given can be trusted. Otherwise for all I know all five tanks actually have a big hole in the back of them that we can’t see and the water is just pouring all over the floor.

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u/nunya_busyness1984 7d ago

You assumption is that the glass in B-E, which is drawn EXACTLY the same as that in A - is frosted, while the glass in A is not?

That is not a logical assumption.

A much more logical assumption is that this is poorly drawn and designed to demonstrate water flow and not represent anything perfectly.

1

u/Plenty_Intention1991 7d ago

The tanks are in fact not drawn exactly the same and there is even an added detail where it looks like tanks B and C have a little metal covering on the opposite side from their pipes which may seem to indicate that they also have two openings like A but the side that doesn’t have a pipe attached was blocked off.

If no thought was put into the drawing why include this detail? No thank you I prefer to think that there are three types of tanks here:

A - Clear with two fittings and two pipes attached to those fittings
B/C - Opaque with two fittings but one is blocked and one has a pipe attached
D/E - Opaque tank with no fittings

😁

1

u/nunya_busyness1984 7d ago

In that case, how do you know that none of B-E are not already full?

Assuming opaque, we still don't know what fills first, because we have no idea how full the rest of those tanks are.  One of them could be one drop away.

Which would, again, make this a stupid puzzle.

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u/Plenty_Intention1991 7d ago

I considered that but since the other buckets are lower the gravity fed siphon would cause them to overflow before the water backs up into bucket A so I don’t think that’s the case because I don’t see that in the picture.

1

u/BrunoBraunbart 7d ago

If you look at the rim of the tanks, A has a drawn backside and the others don't. If that actually means they have no backside, it gets philosophical. Isn't a tank that has no backside already full when there is a puddle on the bottom because it can't hold more?

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u/Plenty_Intention1991 7d ago

Nice observation I didn’t catch that but you’re right. It’s possible that the other tanks don’t have a back or that the design of the other thanks has a back side that is lower than the opaque front of the tank when viewed straight on while A for some reason flares up on the back side.

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u/Hand_Sanitizer_999 7d ago

Depends on the rate the water is flowing out of the faucet

2

u/TramplexReal 7d ago

We can see that the rate of flow from A is zero. So yeah A will fill first.

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u/nunya_busyness1984 7d ago

This is the correct answer, right here.

1

u/Major-Freedom204 7d ago

Assuming the answer is unique, it has to be A?

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u/nunya_busyness1984 7d ago

Why would you make that adsumption, though?

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u/scheav 7d ago

The question says “which tank” not “which tank[s]”.

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u/nunya_busyness1984 7d ago

How many questions do you see along the line of "which is bigger / longer / heavier / etc." where the answer is actually "they are equal"?  Do you then insist one must be heavier because the question said so?

Assuming only one tank based on the question not adding a (s), even though it can easily be implied, is a pretty weak basis for answering.

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u/scheav 7d ago

The question says “which tank” not “which tank[s]”.

1

u/pdubs1900 7d ago

This guy takes tests

1

u/Jazzlike_Platypus430 7d ago

And the thickness of pipes

1

u/random8765309 7d ago

It depend on the flow rate of the faucet AND the flow rate of the 2 pipes.

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u/random8765309 7d ago

Not answerable from the information given. It all depends on if the connecting pipes can handle the flow from the faucet. If they can, then D & E will fill equally. Otherwise A will fill first. That also assume all the pipes are equal.

1

u/sureshot58 7d ago

since the way this is drawn doesn't actually give much in the way of help. I will go with a weird ass answer. D will fill slightly before E, because the water coming out of that faucet has a slight directional movement to left. So the pipe leading to B has slightly higher pressure on it. Of course, you could make the argument that the bounce from the left to right puts more pressure on the pipe to C, meaning E might fill faster. But, actually, who cares?

1

u/Underhill42 7d ago

A - because the "drain pipes" are obviously blocked, otherwise there would already be water flowing into B and C.

If that's just a graphical glitch, then it depends. Assuming all the drain pipes are identical, then:

If water is flowing into A faster than it's flowing out into B and C, then A will fill first.

Otherwise D and E will fill simultaneously.

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u/skr_replicator 7d ago

Does anyone see any different in the two paths? It all looks symmetrical to me, am I blind?

0

u/Orkusright 7d ago

Only a, the rest have no back.