OT - Need a math wizard. - The Orange Mane

Billy Clyde Puckett · 05-11-2006, 03:52 PM

OK I know this is entirely inappropriate, but I have a serious case of brain lock trying to help my 6th grade daughter with her math homework. Can anyone help me set up the formula to solve this problem?

Tank has three different sized valves. If you open only valve A tank empties in 15 minutes, open only valve B and tank empties in 30 minutes, open only valve C and the tank empties in 45 minutes. How long does it take to empty tank of all three valves are opened.

Damn, I feel stupid not being able to do an 11 year old's math. Duh

heydensmom · 05-11-2006, 03:57 PM

don't worry...Can't believe I'm admitting this...but yesterday I was helping my son with his math homework and usually I ace my math classes, but he asked me what 3 step division was......I had no clue...had to look it up to find the answer to help him. I felt like a dumb ass too.

Pendejo · 05-11-2006, 04:01 PM

11.25 minutes using my "New Math" that I just invented.

watermock · 05-11-2006, 04:02 PM

Not sure but I have to call the fuel company.

watermock · 05-11-2006, 04:05 PM

You might think 30minutes, but the question doesn't answer the question of flow at all if all three are opened.

My answer is 30 minutes, approximately.

yavoon · 05-11-2006, 04:06 PM

its a rate question. pretend the tank has 1 gallon, first valve is 1/15th of a gallon/minute second is 1/30th of a gallon in a minute and third is 1/45th of a gallon in a minute.

common denominator makes it 6/90+3/90+2/90 which gives u 11/90 gallons/minute. which means it takes just under 9 minutes.

hope that all worked out.

watermock · 05-11-2006, 04:07 PM

The reality is that unless it's pumped the pressure will change. Have him tell the tearcher that.

It'm terrible at math but they don't give the equation a pressure equation.

Hotrod · 05-11-2006, 04:08 PM

Id just write down that in your opinon opening all 3 valves at the same time would create a pressure valcum which would effect the rate of flow. That being the case its a jacked question.

or you could say 13 minutes whichever you prefer.

Hotrod · 05-11-2006, 04:08 PM

Quote:

Originally Posted by watermock

The reality is that unless it's pumped the pressure will change. Have him tell the tearcher that.

It'm terrible at math but they don't give the equation a pressure equation.

beat me to it .

watermock · 05-11-2006, 04:09 PM

Quote:

Tank has three different sized valves. If you open only valve A tank empties in 15 minutes, open only valve B and tank empties in 30 minutes, open only valve C and the tank empties in 45 minutes. How long does it take to empty tank of all three valves are opened.

ok, that was idiotic. Let me try again.

Hotrod · 05-11-2006, 04:11 PM

Wait it would prolly be less then 10 minutes.

Lev Vyvanse · 05-11-2006, 04:15 PM

Valve a empties the tank at a rate of 1/15th of the tank per minute, valve B empties the tank at 1/30th per minute, and valve C empties the tank at 1/45th per minute. So add them up to get 2/90 + 3/90 + 6/90 = 11/90 all valves per minute. So 11/90*t(time) = 1 which comes out to 8 1/45 minutes.

Boobs McGee · 05-11-2006, 04:15 PM

wouldn't it be 15 minutes?

If A only takes 15, and all of them are open, it wouldn't matter because A is the fastest

Boobs McGee · 05-11-2006, 04:16 PM

now i remember why math was never my strongpoint

Smiling Assassin27 · 05-11-2006, 04:17 PM

when in doubt, the answer is always 'C' or '2'...

smalltowngrll · 05-11-2006, 04:17 PM

Quote:

Originally Posted by bronconia

wouldn't it be 15 minutes?

If A only takes 15, and all of them are open, it wouldn't matter because A is the fastest

They are all three emptying at the same time...it would be under 15 minutes. Valve A would empty the most because it takes less time to empty it all.

broncosteven · 05-11-2006, 04:18 PM

I can do Binary Math & figure out how to subnet IP addresses but I cannot do simple multiplication or addition at the poker table.

Billy Clyde Puckett · 05-11-2006, 04:19 PM

I can gues that it is going to be around 8 minutes, but for the life of me I can't think of what the formula would be . If it was just valve A and valve B, the answer would be 10 minutes as the second drains at half the rate of the first.

Damn that Dave and his diabolical teacher friends

Boobs McGee · 05-11-2006, 04:21 PM

Quote:

Originally Posted by smalltowngrll

They are all three emptying at the same time...it would be under 15 minutes. Valve A would empty the most because it takes less time to empty it all.

absolutely correct there! i was hoping for the "outside the box" lucky guess answer.

carry on class

smalltowngrll · 05-11-2006, 04:24 PM

Quote:

Originally Posted by Big Guy

I can gues that it is going to be around 8 minutes, but for the life of me I can't think of what the formula would be . If it was just valve A and valve B, the answer would be 10 minutes as the second drains at half the rate of the first.

Damn that Dave and his diabolical teacher friends

Are you looking for the algabraic equation?

Lev Vyvanse · 05-11-2006, 04:25 PM

Quote:

Originally Posted by TheTrueOne

Valve a empties the tank at a rate of 1/15th of the tank per minute, valve B empties the tank at 1/30th per minute, and valve C empties the tank at 1/45th per minute. So add them up to get 2/90 + 3/90 + 6/90 = 11/90 all valves per minute. So 11/90*t(time) = 1 which comes out to 8 1/45 minutes.

If this were a real life application, you would have to know a lot more information. The rate of release would decrease as the pressure in the tank decreased. This problem would be a differential equation which = really **** hard math.

Hotrod · 05-11-2006, 04:27 PM

Quote:

Originally Posted by TheTrueOne

If this were a real life application, you would have to know a lot more information. The rate of release would decrease as the pressure in the tank decreased. This problem would be a differential equation which = really **** hard math.

Thats what I said the actual answer can not be found.

smalltowngrll · 05-11-2006, 04:28 PM

x=rate
y=time

x/15+x/30+x/45=y

I believe that would be your equation.

elsid13 · 05-11-2006, 04:29 PM

Quote:

Originally Posted by Hotrod

Id just write down that in your opinon opening all 3 valves at the same time would create a pressure valcum which would effect the rate of flow. That being the case its a jacked question.

or you could say 13 minutes whichever you prefer.

Wrong answer, didn't your Greenpeace friends teach you anything. The answer is "Opening the values would release harmful stuff that would harm Mother Earth. Are you some kinda killer, you evil math teacher?"

PS- I can give you the differential equations for flow but I don't think that what they are learning in 6th.

Hotrod · 05-11-2006, 04:30 PM

Also unless you have 3 people or 3 hands the answer may change depending on which valve you open first and how long it takes you to open each of the two.

05-11-2006, 03:52 PM	#1
Billy Clyde Puckett Billy=Semi Tough Big Guy Looking down on KC, SD and Oakland Join Date: Jan 2004 Location: between 5,000 and 10,000 feet elevation Posts: 12,665 Adopt-a-Bronco: John Elway	OT - Need a math wizard. OK I know this is entirely inappropriate, but I have a serious case of brain lock trying to help my 6th grade daughter with her math homework. Can anyone help me set up the formula to solve this problem? Tank has three different sized valves. If you open only valve A tank empties in 15 minutes, open only valve B and tank empties in 30 minutes, open only valve C and the tank empties in 45 minutes. How long does it take to empty tank of all three valves are opened. Damn, I feel stupid not being able to do an 11 year old's math. Duh

05-11-2006, 04:05 PM	#5
watermock "Hoodie Jr" "Hug me!" Join Date: Jul 2001 Location: Hot Springs, Ouachitah Posts: 77,090	You might think 30minutes, but the question doesn't answer the question of flow at all if all three are opened. My answer is 30 minutes, approximately. Last edited by watermock; 05-11-2006 at 04:23 PM..

05-11-2006, 04:15 PM	#12
Lev Vyvanse Ring of Famer Join Date: Apr 2006 Location: Denver Posts: 3,040	Valve a empties the tank at a rate of 1/15th of the tank per minute, valve B empties the tank at 1/30th per minute, and valve C empties the tank at 1/45th per minute. So add them up to get 2/90 + 3/90 + 6/90 = 11/90 all valves per minute. So 11/90t(time) = 1 which comes out to 8 1/45 minutes. Last edited by Lev Vyvanse; 05-11-2006 at 04:24 PM..*

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05-11-2006, 03:57 PM	#2
heydensmom I'm Jack Bauer! Join Date: Jan 2006 Location: Iowa Posts: 3,577	don't worry...Can't believe I'm admitting this...but yesterday I was helping my son with his math homework and usually I ace my math classes, but he asked me what 3 step division was......I had no clue...had to look it up to find the answer to help him. I felt like a dumb ass too.

05-11-2006, 04:01 PM	#3
Pendejo The off-season. Join Date: Nov 2004 Posts: 2,945 Adopt-a-Bronco: "The Greek"	11.25 minutes using my "New Math" that I just invented.

05-11-2006, 04:02 PM	#4
watermock "Hoodie Jr" "Hug me!" Join Date: Jul 2001 Location: Hot Springs, Ouachitah Posts: 77,090	Not sure but I have to call the fuel company.

05-11-2006, 04:06 PM	#6
yavoon Ring of Famer Join Date: Mar 2004 Posts: 10,260	its a rate question. pretend the tank has 1 gallon, first valve is 1/15th of a gallon/minute second is 1/30th of a gallon in a minute and third is 1/45th of a gallon in a minute. common denominator makes it 6/90+3/90+2/90 which gives u 11/90 gallons/minute. which means it takes just under 9 minutes. hope that all worked out.

05-11-2006, 04:07 PM	#7
watermock "Hoodie Jr" "Hug me!" Join Date: Jul 2001 Location: Hot Springs, Ouachitah Posts: 77,090	The reality is that unless it's pumped the pressure will change. Have him tell the tearcher that. It'm terrible at math but they don't give the equation a pressure equation.

05-11-2006, 04:08 PM	#8
Hotrod Self Appointed Expert aka Dortoh Join Date: Aug 2003 Posts: 25,136 Adopt-a-Bronco: Miss I	Id just write down that in your opinon opening all 3 valves at the same time would create a pressure valcum which would effect the rate of flow. That being the case its a jacked question. or you could say 13 minutes whichever you prefer.

05-11-2006, 04:11 PM	#11
Hotrod Self Appointed Expert aka Dortoh Join Date: Aug 2003 Posts: 25,136 Adopt-a-Bronco: Miss I	Wait it would prolly be less then 10 minutes.

05-11-2006, 04:15 PM	#13
Boobs McGee I promise to stay alive till the day that I die Join Date: Jan 2006 Location: Glendale Posts: 5,014 Adopt-a-Bronco: CassiusVAAAUGHN	wouldn't it be 15 minutes? If A only takes 15, and all of them are open, it wouldn't matter because A is the fastest

05-11-2006, 04:16 PM	#14
Boobs McGee I promise to stay alive till the day that I die Join Date: Jan 2006 Location: Glendale Posts: 5,014 Adopt-a-Bronco: CassiusVAAAUGHN	now i remember why math was never my strongpoint

05-11-2006, 04:17 PM	#15
Smiling Assassin27 STOP! KIPER TIME! Join Date: Dec 2002 Location: In a van down by the river Posts: 10,957 Adopt-a-Bronco: Von Miller	when in doubt, the answer is always 'C' or '2'...

05-11-2006, 04:18 PM	#17
broncosteven The Kranz Dictum MWA: Flight Director Join Date: Jun 2005 Location: Tranquility Base Posts: 29,015 Adopt-a-Bronco: MONEYBALL #38	I can do Binary Math & figure out how to subnet IP addresses but I cannot do simple multiplication or addition at the poker table.

05-11-2006, 04:19 PM	#18
Billy Clyde Puckett Billy=Semi Tough Big Guy Looking down on KC, SD and Oakland Join Date: Jan 2004 Location: between 5,000 and 10,000 feet elevation Posts: 12,665 Adopt-a-Bronco: John Elway	I can gues that it is going to be around 8 minutes, but for the life of me I can't think of what the formula would be . If it was just valve A and valve B, the answer would be 10 minutes as the second drains at half the rate of the first. Damn that Dave and his diabolical teacher friends

05-11-2006, 04:28 PM	#23
smalltowngrll Orange Blue Join Date: Dec 2005 Location: Bend, OR Posts: 8,038 Adopt-a-Bronco: dortoh	x=rate y=time x/15+x/30+x/45=y I believe that would be your equation.

05-11-2006, 04:30 PM	#25
Hotrod Self Appointed Expert aka Dortoh Join Date: Aug 2003 Posts: 25,136 Adopt-a-Bronco: Miss I	Also unless you have 3 people or 3 hands the answer may change depending on which valve you open first and how long it takes you to open each of the two.