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BS.Dos.
Joined: 29 Mar 2007
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 Posted: Tue Jan 08, 2008 6:21 pm Post subject: Maths Help |
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I need to calculate the difference between two numbers as a percentage, which I think I've done, but need someone to check it for me.
The two numbers are:
544
413
I calculated the difference as being 24%
413 - 544 = 131
131/544 = 0.24 * 100 = 24%
Does this seem right? I'm nursing a bit of a hangover this morning and I can't think straight.
School boy stuff, but I'm no longer a school boy I'm afraid. |
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cbclark4
Joined: 20 Aug 2006
Location: Masan
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| Posted: Tue Jan 08, 2008 6:37 pm Post subject: |
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The difference of 413 and 544 is 131.
If 544 is 100% then 413 is 75.9% and 131 is 24.1%.
Therefore the difference between 413 and 544 is 24.1% of the total. |
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BS.Dos.
Joined: 29 Mar 2007
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| Posted: Tue Jan 08, 2008 6:40 pm Post subject: |
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Thanks for that.
I thought it was right but just wanted to check. |
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ernie
Joined: 05 Aug 2006
Location: asdfghjk
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| Posted: Tue Jan 08, 2008 7:02 pm Post subject: |
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but if you have 413 now and you want to have 544, the percentage increase will be different because 413 would equal 100%...
your question is ambiguous: my answer would be 31.7%... |
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BS.Dos.
Joined: 29 Mar 2007
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| Posted: Tue Jan 08, 2008 7:26 pm Post subject: |
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I needed to know what the difference is (%) between the bigger and the smaller number, not the other way round.
Apologies if I didn't make that clear. |
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Juregen
Joined: 30 May 2006
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| Posted: Tue Jan 08, 2008 8:17 pm Post subject: |
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More accurate would be
544 -> 413 = (413-544)/544 = -24.08%
413 -> 544 = (544-413)/413 = +31.72% |
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Samantha
Joined: 20 Jul 2006
Location: Jinan-dong Hwaseong
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| Posted: Tue Jan 08, 2008 9:56 pm Post subject: |
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or if that doesn't help you can do a simple is over of percentage ration
The difference between 413 and 544 (544-413=131) is what percent (x) of the total (544).
131/544= x/100 cross multiply then divide
131*100=544x
13100/544=x
x=24.08%
(at least this is the show your work drawn version I was taught in school and also tutored for several semesters)  |
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BS.Dos.
Joined: 29 Mar 2007
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| Posted: Wed Jan 09, 2008 8:02 pm Post subject: |
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More help required.
I don't have a hangover today so I've no excuse for not being able to work this out.
Here's the problem:
1000kg (Cassava) produces
366kg of ethanol
How much raw cassava will I need to produce 100,000 tons of ethanol?
(1 ton = 1000kg) |
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Samantha
Joined: 20 Jul 2006
Location: Jinan-dong Hwaseong
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| Posted: Wed Jan 09, 2008 8:27 pm Post subject: |
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| BS.Dos. wrote: |
More help required.
I don't have a hangover today so I've no excuse for not being able to work this out.
Here's the problem:
1000kg (Cassava) produces
366kg of ethanol
How much raw cassava will I need to produce 100,000 tons of ethanol?
(1 ton = 1000kg)<---are you talking metric ton or US ton? this is a metric ton...1 ton=1000kg....an US ton is 1 ton=907 kg. |
set the ratio again
working with the metric ton ton:Kg--> 1:1000....we need 100K ton so we need 100,000*1,000=100,000,000 kg.
so back to the original information
Cassava:ethanol
1,000kg:366kg
xkg:100,000,000kg
cross multiply and divide
1,000*100,000,000/366=x
100,000,000,000/366=x
x=273224043.7158..... so you need 273,224,044kg of the original product to get the 100K ton of ethanol. |
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BS.Dos.
Joined: 29 Mar 2007
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| Posted: Wed Jan 09, 2008 8:33 pm Post subject: |
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Thanks.
I was trying to work it out thus:
1000/366
2.73
2.73*100,000,000
273,000,000 kg
273,000 tons
I kind of figured it out after I'd posted, but just wanted confirmation.
Thanks. |
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Samantha
Joined: 20 Jul 2006
Location: Jinan-dong Hwaseong
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| Posted: Thu Jan 10, 2008 12:03 am Post subject: |
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| BS.Dos. wrote: |
Thanks.
I was trying to work it out thus:
1000/366
2.73
2.73*100,000,000
273,000,000 kg
273,000 tons
I kind of figured it out after I'd posted, but just wanted confirmation.
Thanks. |
No prob. You were close...sort of...just off quite a few place values. You forgot to convert ton to kilo so everything was in the same units. No worries. Any other questions? I haven't had a reason to do any kind of major math for a couple of years now, at least nothing outside of adding up bills or balancing the bank book. |
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BS.Dos.
Joined: 29 Mar 2007
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| Posted: Thu Jan 10, 2008 12:34 am Post subject: |
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| Quote: |
| Any other questions? I haven't had a reason to do any kind of major math for a couple of years now, at least nothing outside of adding up bills or balancing the bank book. |
Well, I do as it goes.
Continuing with the same theme:
Now that we've established the total amount of raw material needed to produce 100,000 tons of ethanol, I now need to calculate some of the process outputs.
Inputs
1000kg (cassava)
4293kg (water)
5293 = 366kg ethanol
The total inputs are:
273,224 tons (Raw cassava)
1,172,950 tons (water)
100,000 tons ethanol
As every 1000kg of raw cassava requires 4293kg of water:
273,224*4.293 = 1,172,950 (I think this is right)
Total input
1,446,174 tons
Outputs
Every 5293kg (1000+4293) of raw material produces:
338kg CO2
2kg water vapor
4441kg of water effluent
131kg other waste
I have to calculate the total weight (kg/ton) of the above outputs in respect of the gross inputs.
I'll have a go and post my answers once I've done it.
*EDIT*
Sorry, forgot to add that once you calculated the 338kg (CO2) and the 2kg (water vapor) the new total becomes 4953kg.
338+2 - 5293 = 4953 kg
You need to calculate the 4441 (water) and the 131 (other) from 4953 not 5293kg. |
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BS.Dos.
Joined: 29 Mar 2007
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| Posted: Thu Jan 10, 2008 1:38 am Post subject: |
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Ok,
1,446,174/5.293 = 273,223 (tons)
273,223*338 (CO2) = 92,349,374/1000
= 92,349 tons CO2
1,446,174/5.293 = 273,223 (tons)
273,223*2 (water vapor) = 546,446/1000
= 546.4 tons water vapor
1,446,174/4.953 = 291,979
291,979*4441 (water effluent) = 1,296,678,739/1000
=1,296,678 tons water effluent (This is more water than what goes in. However, the raw cassava [1000kg] contains 150kg of water, hence why more water comes out than what appears to go in. Additionally, after all the outputs have been extract there is 381kg of ethanol remaining. Of this 381kg, 15kg is additional water that is evaporated (I presume) as it dehydrates, leaving 366kg of ethanol behind)
1,446,174/4.953 = 291,979
291,979*131 (other waste) = 38,249,249/1000
=38,249 tons other waste
1,296,678 (88.66%)
92,349 (6.38%)
38,249 (2.64%)
546.4 (0.03%)
1,427,822 tons (97.71%)
1,446,174 - (total inputs)
1,427,822 (total outputs)
18,352 tons short. Either I've made a mistake or it's the loss of all those part tons that I didn't carry over. |
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tzechuk
Joined: 20 Dec 2004
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| Posted: Thu Jan 10, 2008 4:19 am Post subject: |
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| BS.Dos. wrote: |
Thanks.
I was trying to work it out thus:
1000/366
2.73
2.73*100,000,000
273,000,000 kg
273,000 tons
I kind of figured it out after I'd posted, but just wanted confirmation.
Thanks. |
This is how I do it.
(1000/366)*1000 (kg)*100,000(ton) = 273,224,043
Do the same with the others. |
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laogaiguk
Joined: 06 Dec 2005
Location: somewhere in Korea
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| Posted: Thu Jan 10, 2008 4:23 am Post subject: |
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| This is actually a study on the math skills of EFL teachers in Korea, isn't it? |
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