My Math Forum  

Go Back   My Math Forum > High School Math Forum > Probability and Statistics

Probability and Statistics Basic Probability and Statistics Math Forum


Reply
 
LinkBack Thread Tools Display Modes
September 23rd, 2017, 07:46 AM   #1
Newbie
 
Joined: Sep 2017
From: Romania

Posts: 4
Thanks: 0

Added percentages

Hi

I have this problem:

On a motorway, percents for vehicles at some hour are:

Urban Cars 7%
Rural Cars 6%
Trucks 5%

For Vehicles Percent I do this:

7+6+5=18
100+100+100=300

18/300=0.060*100=6.0%

Now I want to have only Cars and Trucks

7+6=13
100+100=200

13/200=0.065*100=6.5%

Cars 6.5%
Trucks 5%

New Total Vehicles Percent:

6.5+5=11.5
100+100=200

11.5/200=0.0575*100=5.75%

What is wrong here? Why are not equale?

Thanks for your help
Carcalete is offline  
 
September 23rd, 2017, 09:02 AM   #2
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 10,688
Thanks: 701

Quote:
Originally Posted by Carcalete View Post
On a motorway, percents for vehicles at some hour are:

Urban Cars 7%
Rural Cars 6%
Trucks 5%

For Vehicles Percent I do this:

7+6+5=18
100+100+100=300

18/300=0.060*100=6.0%
NO. Vehicle percent is simply 7+6+5 = 18%.
(wonder what makes the difference of 82%: bicycles?!)

Is this a classroom problem?
Denis is offline  
September 23rd, 2017, 01:20 PM   #3
Newbie
 
Joined: Sep 2017
From: Romania

Posts: 4
Thanks: 0

No, I have a real problem with this, adding percent when you know only percent.
First example was not very clear, I think. I made another.

Three tanks of fuel, tank cappacity - fuel in tank - percent full.

300L - 150L - 50%
200L - 50L - 25%
100L - 50L - 50%
-----------------------
600L - 250L - 250/600~0.417 = 41.7%

Is simple and clear.

Now do this when you know only percent.

With your solution:

50+25+50 = 125%

and is not real.
Carcalete is offline  
September 23rd, 2017, 02:49 PM   #4
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 10,688
Thanks: 701

Quote:
Originally Posted by Carcalete View Post
Three tanks of fuel, tank cappacity - fuel in tank - percent full.

300L - 150L - 50%
200L - 50L - 25%
100L - 50L - 50%
-----------------------
600L - 250L - 250/600~0.417 = 41.7%

Is simple and clear.
Yes, it is simple and clear...NOTHING like your 1st example.

BUT given only the 50%, 25% and 50% makes no sense:
the breakdown is NOT unique; this would fit:

2000L - 1000L - 50%
0004L - 0001L - 25%
0222L - 0111L - 50%
--------------------------
2226L - 1112L - 1112/2226 = ~49.955%

See your teacher to learn the basics of percentages.
This is not a classroom.
Denis is offline  
September 23rd, 2017, 04:54 PM   #5
Global Moderator
 
greg1313's Avatar
 
Joined: Oct 2008
From: London, Ontario, Canada - The Forest City

Posts: 7,595
Thanks: 938

Math Focus: Elementary mathematics and beyond
Quote:
Originally Posted by Carcalete View Post
Hi

I have this problem:

On a motorway, percents for vehicles at some hour are:

Urban Cars 7%
Rural Cars 6%
Trucks 5%

For Vehicles Percent I do this:

7+6+5=18
100+100+100=300

18/300=0.060*100=6.0%

Now I want to have only Cars and Trucks

7+6=13
100+100=200

13/200=0.065*100=6.5%

Cars 6.5%
Trucks 5%

New Total Vehicles Percent:

6.5+5=11.5
100+100=200

11.5/200=0.0575*100=5.75%

What is wrong here? Why are not equale?

Thanks for your help
7/100 + 6/100 + 5/100 = 18/100 = 18%. So you've made some fundamental errors. Can you correct them?

Last edited by greg1313; September 23rd, 2017 at 08:01 PM.
greg1313 is offline  
September 24th, 2017, 12:13 AM   #6
Newbie
 
Joined: Sep 2017
From: Romania

Posts: 4
Thanks: 0

For this problem I have only a graphic evolution in time, with percentages for categories, and nothing else. Non sens or not, ....., no comment.

Anyway thanks for your help and kind advices.
I try to find more, on my classroom .... back on '80.

I'm sorry for waste your precious time Denis!

Kind Regards!
Carcalete is offline  
September 24th, 2017, 04:37 AM   #7
Math Team
 
Joined: Oct 2011
From: Ottawa Ontario, Canada

Posts: 10,688
Thanks: 701

Quote:
Originally Posted by Carcalete View Post
I'm sorry for waste your precious time Denis!
No problems...pleasure was indeed all mine
Denis is offline  
September 27th, 2017, 04:13 AM   #8
Newbie
 
Joined: Sep 2017
From: Romania

Posts: 4
Thanks: 0

Eventually I used data normalization. It's not the most correct method, I think, but it gives a better picture of the data distribution.

Thus, regardless of the method used in adding, the normalized result is the same, and can be compared to its normalized components.

I tried for normalization the following methods:

Scale between 0 and 1
En [If] (Max ([E]) = Min ([E]), 0.5, ([E] - Min ([E]

Normalize by mean
En = [E] / Avg ([E])

Normalize by mean with new interval
En = [E] * Avg ([A]) / Avg ([E])

E - are the initial values
A - are the new interval for values
En - are the new normalized values

Other normalization methods can be found here:
https://docs.tibco.com/pub/spotfire/...ng_columns.htm

For my situation, the best method was:

Normalize by mean with new interval
En = [E] * Avg ([A]) / Avg ([E])

Ex.
AMin: 0.00%
AAvg: 50.00%
AMax: 100.00%


No Trucks NTrucks DayTrucks NDayTrucks Cars NCars Total NTotal Total/3 NTotal/3
0 4.40% 52.25% 2.10% 24.88% 1.60% 19.32% 8.10% 32.21% 2.70% 32.21%
1 4.30% 51.06% 1.90% 22.51% 1.10% 13.28% 7.30% 29.03% 2.43% 29.03%
2 4.20% 49.88% 1.70% 20.14% 1.00% 12.07% 6.90% 27.44% 2.30% 27.44%
3 4.10% 48.69% 1.50% 17.77% 0.90% 10.87% 6.50% 25.85% 2.17% 25.85%
4 4.20% 49.88% 1.80% 21.32% 1.10% 13.28% 7.10% 28.24% 2.37% 28.24%
5 4.30% 51.06% 2.20% 26.06% 1.20% 14.49% 7.70% 30.62% 2.57% 30.62%
6 4.25% 50.47% 2.80% 33.17% 2.50% 30.18% 9.55% 37.98% 3.18% 37.98%
7 4.15% 49.28% 5.00% 59.23% 4.50% 54.33% 13.65% 54.28% 4.55% 54.28%
8 3.95% 46.91% 7.10% 84.11% 6.90% 83.30% 17.95% 71.38% 5.98% 71.38%
9 3.90% 46.31% 6.90% 81.74% 7.70% 92.96% 18.50% 73.57% 6.17% 73.57%
10 4.50% 53.44% 6.90% 81.74% 5.60% 67.61% 17.00% 67.61% 5.67% 67.61%
11 4.50% 53.44% 6.90% 81.74% 5.30% 63.98% 16.70% 66.41% 5.57% 66.41%
12 4.20% 49.88% 6.70% 79.37% 5.50% 66.40% 16.40% 65.22% 5.47% 65.22%
13 4.20% 49.88% 6.50% 77.00% 5.70% 68.81% 16.40% 65.22% 5.47% 65.22%
14 4.05% 48.10% 6.60% 78.18% 6.40% 77.26% 17.05% 67.80% 5.68% 67.80%
15 3.95% 46.91% 6.60% 78.18% 7.40% 89.34% 17.95% 71.38% 5.98% 71.38%
16 4.00% 47.50% 6.00% 71.08% 8.20% 98.99% 18.20% 72.38% 6.07% 72.38%
17 4.00% 47.50% 5.00% 59.23% 7.00% 84.51% 16.00% 63.63% 5.33% 63.63%
18 4.10% 48.69% 4.20% 49.75% 5.30% 63.98% 13.60% 54.08% 4.53% 54.08%
19 4.20% 49.88% 3.20% 37.91% 4.30% 51.91% 11.70% 46.53% 3.90% 46.53%
20 4.30% 51.06% 2.80% 33.17% 3.20% 38.63% 10.30% 40.96% 3.43% 40.96%
21 4.30% 51.06% 2.50% 29.62% 2.80% 33.80% 9.60% 38.18% 3.20% 38.18%
22 4.50% 53.44% 2.20% 26.06% 2.40% 28.97% 9.10% 36.19% 3.03% 36.19%
23 4.50% 53.44% 2.20% 26.06% 1.80% 21.73% 8.50% 33.80% 2.83% 33.80%

Min 3.90% 46.31% 1.50% 17.77% 0.90% 10.87% 6.50% 25.85% 2.17% 25.85%
Avg 4.21% 50.00% 4.22% 50.00% 4.14% 50.00% 12.57% 50.00% 4.19% 50.00%
Max 4.50% 53.44% 7.10% 84.11% 8.20% 98.99% 18.50% 73.57% 6.17% 73.57%

Have A Nice Day!
Carcalete is offline  
Reply

  My Math Forum > High School Math Forum > Probability and Statistics

Tags
added, percentages



Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
What volume of water should be added? pianist Chemistry 6 July 27th, 2017 04:08 PM
What happens to the temperature when salt is added to water? pianist Chemistry 3 May 29th, 2017 01:32 AM
Square of x , added to one is not equal to n! jim198810 Number Theory 10 May 25th, 2015 07:09 AM
Percentages problem need help adding percentages please BellEnd Elementary Math 4 May 25th, 2012 01:56 PM





Copyright © 2017 My Math Forum. All rights reserved.