Math geeks all hands on deck!

  • Thread starter Thread starter Ugly
  • Start date Start date
  • Christian Chat is a moderated online Christian community allowing Christians around the world to fellowship with each other in real time chat via webcam, voice, and text, with the Christian Chat app. You can also start or participate in a Bible-based discussion here in the Christian Chat Forums, where members can also share with each other their own videos, pictures, or favorite Christian music.

    If you are a Christian and need encouragement and fellowship, we're here for you! If you are not a Christian but interested in knowing more about Jesus our Lord, you're also welcome! Want to know what the Bible says, and how you can apply it to your life? Join us!

    To make new Christian friends now around the world, click here to join Christian Chat.
I think it's 8 hours because it took too long for the other faucet to fill up so it got turned off HEHE.
 
cUXBz9t.jpg
 
Ugly said:
[...]
You have one faucet that fills up a pool in 24 hours.
You have second faucet that fills up a pool in 8 hours.
If you run both faucets in one pool, how long does it take to fill up the pool?

I figured out i was approaching the answer wrong. So now i understand where i went wrong. Now i just can't figure out the math to the correct logical approach. So now i understand how to get to the correct answer, I just don't know the math itself.

Will be fun to see everyones answers either way.
Click to expand...

Seems to me that one logical approach is to determine the combined fill rates, and then work backwards from that rate to determine the time to fill one pool.

For example, the two fill rates are: 1 pool per 24 hours, and 1 pool per 8 hours. Combined, the math is 1/24 + 1/8 = 4/24. In human speak, that means the combined fill rate is 4 pools can be filled every 24 hours. Simplified to 1 pool, that's 1 pool filled every 6 hours.
 
Last edited:
I just wanted to say how much I really enjoyed this thread!!

Although it's obvious I'm not attempting to answer the question (cough, cough :rolleyes:), it's really a lot of fun and quite interesting to read how people have come up with the answer. Unfortunately, math taps into the part of my brain that either isn't there or just doesn't work.

But I think this would be an awesome idea for a regular thread series: "Math Problem of the Week" or general problems that people could offer their solutions to... (Wallpapering? Changing out the hardware in the back of your toilet? Keeping plants alive? Not that any of this would apply to me... Again... cough, cough, cough.)

It was just really cool to see everyone dig in and come up with their own answers. Even the non-math-related ones! :)
 
Last edited:
PopClick said:
Assume that the pool is 48 gallons.

Faucet 1 must be running at 2 gallons per hour. (48 / 24 = 2)

Faucet 2 must be running at 6 gallons per hour. (48 / 8 = 6)

So if you run them both, you have a flow of 8 gallons per hour (2 + 6 = 8), therefore it would take 6 hours to fill up the pool. (8 * 6 = 48)

...Am I right?
Click to expand...


As a veteran house remodel-er, and a decent plumber, I must protest the ruling. (I am sure Oncefallen will back me up on this)

We have to know the pipe setup, to know if both faucets will pump at their individual capacity when both are on. We'll need to see the pump rating as well, if the swimming pool isn't on a water main.

Also, the rate of evaporation is a constant, assuming constant temperature and humidity. Therefore the two faucets will fill faster than the combined capacity.
 
This would've been my test paper. I was pretty lucky with answers sometimes...

Math test.jpg
 

Attachments

^^^ Kenthomas, in the 5 years I've been here...

This would definitely be on my list of 5 Best Posts I've Ever Seen On CC!!!

I'm still laughing!!! :)
 
We seriously need a random comic strip or drawing thread where we respond to each other in silly drawings. Kenthomas, that was hilarious.
 
the correct answer is already posted but being a math geek, i want to work it out for myself too :)

let x be the rate of the first faucet, y the rate of the second faucet, in units-per-hour
and let z be the volume of the pool in units.

then 24*x = z = 8*y

so x = z/24
and y = z/8

let t be the time it takes to fill up the pool with both faucets.

then

x*t + y*t = z
or making substitutions,
(z/24)*t + (z/8)*t = z

z*(1/24 +1/8) = z/t

(1/24 + 3/24) = 1/t

4/24 = 1/6 = 1/t

→ t = 6 hours


 
i like how everyone assumed the pools are either the same pool or of the same size, but neither were said. so depending on your assumptions, this probolem is unsolvable
 
todo said:
i like how everyone assumed the pools are either the same pool or of the same size, but neither were said. so depending on your assumptions, this probolem is unsolvable
Click to expand...

i'd like to rephrase my answer in terms of an "unit pool"

from there, it's trivially only a scaling problem using the unitless volumetric ratio of (any given pool)/(unit pool)
 
JimJimmers said:
As a veteran house remodel-er, and a decent plumber, I must protest the ruling. (I am sure Oncefallen will back me up on this)

We have to know the pipe setup, to know if both faucets will pump at their individual capacity when both are on. We'll need to see the pump rating as well, if the swimming pool isn't on a water main.

Also, the rate of evaporation is a constant, assuming constant temperature and humidity. Therefore the two faucets will fill faster than the combined capacity.
Click to expand...

As I was reading through this thread this type of post was on my mind. I burst out laughing when I saw that someone beat me to it.
 
JimJimmers said:
As a veteran house remodel-er, and a decent plumber, I must protest the ruling. (I am sure Oncefallen will back me up on this)

We have to know the pipe setup, to know if both faucets will pump at their individual capacity when both are on. We'll need to see the pump rating as well, if the swimming pool isn't on a water main.

Also, the rate of evaporation is a constant, assuming constant temperature and humidity. Therefore the two faucets will fill faster than the combined capacity.
Click to expand...

Oncefallen said:
As I was reading through this thread this type of post was on my mind. I burst out laughing when I saw that someone beat me to it.
Click to expand...


Leave it to the Jim's!!!

"Wonder Jim Powers, ACTIVATE!!! Form of, Professional Contractor! Shape of, Evaporation Expert Extraordinaire!"
 
You must log in or register to reply here.
Top Bottom
Back