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[Neonivek]

Okay...

My "Creative" [read: Content] Writing teacher says, yes, I developed a voice in the assignment...

a creepy one.


I'm not sure if this is good or bad...

Ask Tim Burton?

[PyroDesu]

Okay...

My "Creative" [read: Content] Writing teacher says, yes, I developed a voice in the assignment...

a creepy one.


I'm not sure if this is good or bad...

Ask Tim Burton?

Not that creepy, I think.

Just... Creepy. To her.

[Leatra]

Let's be honest, if you can't tell the difference between the legs of a chicken and the legs of a horse, you have a bigger problem than how many of each you have.

Uh... Some of them were half chicken half horse? horsechicken

Maybe we should invent a new metaphor.

[PyroDesu]

Let's be honest, if you can't tell the difference between the legs of a chicken and the legs of a horse, you have a bigger problem than how many of each you have.

Uh... Some of them were half chicken half horse? horsechicken

Maybe we should invent a new metaphor.

There are 15 fruit, but only apples and pears, in a bowl. 5 of them are apples. How many pears are there?

[Bauglir]

Chickataurs? Fearsome creatures, those. I hear that they can turn a man to stone with a beat of their wings! Not women, though. Or more than one man. It's kind of a limited thing. Still, they're also surprisingly good knife-fighters, so I'd hate to irritate one.

[Leatra]

There are 15 units of salt or sugar in a cup. We know there are 5 units of sugar. How many units of salt are there?

That one is logical. They look the same.

Chickataurs? Fearsome creatures, those. I hear that they can turn a man to stone with a beat of their wings! Not women, though. Or more than one man. It's kind of a limited thing. Still, they're also surprisingly good knife-fighters, so I'd hate to irritate one.

Also I heard they ate children in grade school.

[Neonivek]

There are 15 units of salt or sugar in a cup. We know there are 5 units of sugar. How many units of salt are there?

That one is logical. They look the same.

The answer is 15 or 10

It just isn't asked in a logical way.

[Urist Imiknorris]

Here, try this:

A 400 gallon tank initially contains 100 gallons of brine containing 50 lb. of salt. Brine containing 1 lb of salt per gallon enters the tank at 5 gallons per minute, and the well-mixed brine in the tank flows out at a rate of 3 gallons per minute. How much salt will the tank contain when it is full?

[Neonivek]

A 400 gallon tank initially contains 100 gallons of brine containing 50 lb. of salt. Brine containing 1 lb of salt per gallon enters the tank at 5 gallons per minute, and the well-mixed brine in the tank flows out at a rate of 3 gallons per minute. How much salt will the tank contain when it is full?

Assuming all things constant

Let me see... We want the amount of Salt so X, the Tank already contains 50 pounds of Salt (X = 50), however we have 400 pounds of water with a specific amount of salt added but with an outflow and inflow where the salt doesn't exit the tank.

The water fills at a rate of 2 gallons a minute, but each gallon adds 5 salt.

((400-100)/(5-3))*5 = X + 50
((400-100)/2)*5 = X + 50
700 = X

700 pounds of Salt!?! I may have made a mistake somewhere. Though it seems correct.

Now I just need to turn that into a formula and I'd be golden. Except I don't know QUITE how to do this equasion as a whole... except I guess

5((400-100)/(5-3))-50= X

[Leatra]

Let's rewrite the mathematics

That is a very good question. But unfortunately, I cannot solve a question if a teacher doesn't make me memorize a formula and explain the technique to solve this question. I can count the legs of some chickens and horses though! Yay me! After solving that kind of questions for like 500 times in grade school, I have written the way to solve them in my brain. Isn't our education system great?

[lemon10]

A 400 gallon tank initially contains 100 gallons of brine containing 50 lb. of salt. Brine containing 1 lb of salt per gallon enters the tank at 5 gallons per minute, and the well-mixed brine in the tank flows out at a rate of 3 gallons per minute. How much salt will the tank contain when it is full?

Assuming all things constant

Let me see... We want the amount of Salt so X, the Tank already contains 50 pounds of Salt (X = 50), however we have 400 pounds of water with a specific amount of salt added but with an outflow and inflow where the salt doesn't exit the tank.

The water fills at a rate of 2 gallons a minute, but each gallon adds 5 salt.

((400-100)/(5-3))*5 = X + 50
((400-100)/2)*5 = X + 50
700 = X

700 pounds of Salt!?! I may have made a mistake somewhere. Though it seems correct.

Now I just need to turn that into a formula and I'd be golden. Except I don't know QUITE how to do this equasion as a whole... except I guess

5((400-100)/(5-3))-50= X

You made a mistake. Water enters at 1 pound of salt per gallon, and 5 gallons per minute. And it doesn't stay constant either, since the amount of salt flowing out increases as the concentration of brine in the tank increases (starting at 1/2 lb per gallon and increasing consistently).

[Bauglir]

The trick is that the concentration of the outflow depends on the point in time.

Where y is the salt quantity at time x,

y=50+5x-(3y/(100+2x)) maybe?

Only that's not quite right. My gut tells me that to properly model the outflow requires a bit of calculus, but I can't explain why properly. It seems like the sort of problem that requires it, though, since you have to model one rate of change in terms of another.

EDIT: Ninja'd

[Neonivek]

You made a mistake. Water enters at 1 pound of salt per gallon, and 5 gallons per minute. And it doesn't stay constant either, since the amount of salt flowing out increases as the concentration of brine in the tank increases (starting at 1/2 lb per gallon and increasing consistently

I still don't understand my mistake exactly.

Every 2 units of increase is essentially 5 pounds of Salt.

However salt is also flowing out? So I am working with percent over time issue and I have to use that initial 50 and 100.

My gut tells me that to properly model the outflow requires a bit of calculus, but I can't explain why properly

I don't believe you have to. However that information changes the entire formula.

I guess what you COULD do is make it a percent.

In an ideal world the water would be 1/1 pound of salt to gallon of water. However the water is changing every frame by 2 by a percent compounded...

Ohh my goodness... Compounding! AHHH!

[RedKing]

You made a mistake. Water enters at 1 pound of salt per gallon, and 5 gallons per minute. And it doesn't stay constant either, since the amount of salt flowing out increases as the concentration of brine in the tank increases (starting at 1/2 lb per gallon and increasing consistently

I still don't understand my mistake exactly.

Every 2 units of increase is essentially 5 pounds of Salt.

However salt is also flowing out? So I am working with percent over time issue and I have to use that initial 50 and 100.

My gut tells me that to properly model the outflow requires a bit of calculus, but I can't explain why properly

I don't believe you have to. However that information changes the entire formula.

I guess what you COULD do is make it a percent.

In an ideal world the water would be 1/1 pound of salt to gallon of water. However the water is changing every frame by 2 by a percent compounded...

Ohh my goodness... Compounding! AHHH!

That's why you need calculus. Because the change in the salinity of the water (and thus the salinity of the outflow, and thus the amount by which the salt is changing, because you have a static integer input minus a changing output) is a smooth curve rather than a series of step changes. And it's not a simple geometric progression.

[Vector]

Oh my god =/

I leave ten minutes and you guys are giving me flashbacks to calculus.  Oh god, oh no, the misery.


Third fucking B- in a row on a paper.  Dammit.  At least I've got a meeting this Friday so I can figure out how to make my homework perfecter.