11.4 Practical Examples

Here are some real-life examples of uses of percentages.

• If you buy something and sell it, the difference between the two prices is a profit or a loss. It's given as a percentage of the buying price. If you buy something for $20 and sell it for $15 you make a loss of $5 or 25%.
• When you buy something you may be offered a discount. This is a reduction in the price. It's usually given as a percentage. If the price is normally $20 and you get a 10% discount, you only pay $18.
• If a bank helps you to buy an item, you may have to pay back more than you borrow. This is the interest that the bank charges. It's given as a percentage of the cost. If a car costs $20000 and the rate of interest is 3%, you will pay $20600.
• If you buy something the price may include a tax. This is called a purchase tax. When you earn money you may have to pay tax on what you earn. This is called income tax.

I have three questions to ease your understanding.

Questions

1. A woman bought an old chair for $240. She sold it for $300. Work out the percentage profit.

Profit: 300 - 240 = 60. 60/240*100% = 25%

2. A man bought a car for $15900. He sold it for $9500. Work out the percentage loss.

Loss: 15900 - 9500 = 6400. 6400/15900*100% = 40%

3. A bottle of grape juice costs $6.50. If you buy six bottles you can get 10% discount. Work out how much you save if you buy six bottles. 

=> 6.50*6 = 39. 39*90% = 35,10.

39 - 35,10 = $3,9

11.3 Percentage Changes

You can use percentages to describe a change in a quantity. It could be a decrease or an increase. A percentage is always calculated as a percentage of the initial value. The initial value is 100%. It's important to choose the correct value to be 100%. I have three questions to ease your understanding.

Question

1. Here are the prices of three items in Alain's shop.
Game $40   Phone $120  Computer $500
Alain increases all the prices by $10. Find the percentage increase for each item.

Game: The initial value is 40. So 10/40*100% = 25%
Phone: The initial value is 120. So 10/120*100% = 8,3%
Computer: The initial value is 500. So 10/500*100%

2. These are the masses of three children on April.
Luke 6kg   Bridget 14kg   Thomas 25kg
Over a year, the mass of each of them increased by 10%. Work out the new mass of each child.

Luke: 6*110% = 6,6 
Bridget: 14*110% = 15,4
Thomas: 25*110% = 27,5

3. The price of a car was $20000. In a sale, the price decreased by 4%. After the sale it increased by 4%.
Ahmad says "The price after the sale is 20000 again"
a. What mistake has Ahmad made?
b. What is the correct price after the sale?

a) He misplace the initial value for the price after sale. The first initial value is 20000. the second initial value is 19200. So the result won't be the same as before.

b) 19200*104% = 19968

11.2 Comparing Different Quantities

You will often need to compare groups that are different sizes.
In this case, it'll be easy if you use percentages.

                                  
I have three questions to ease your understanding.

Questions

1. There were 270 people in cinema. There were 168 women and 102 men. There were 152 people in a theatre. Theatre were 78 women and 74 men.

a. Work out the percentage of women in each venue.
b. Work out the percentage of men in each venue.

a) cinema: 168/270*100% = 62%
    theatre: 78/152*100% = 51%

b) cinema: 102/270*100% = 37%
     theatre: 74//152*100% = 49%

2. In Alphatown there are 5400 young people aged 18 or less. There are 9300 aged over 18. in Betatown there are 9300 young people aged 18 or less. There are 21600 aged over 18.

a. Calculate the percentage of young people in each town.
b. Which town has the greater proportion of young people?

a)
 Alphatown:  5400/14700*100% = 37% {5400 is the amount of young people, 14700 is the amount of all people.}
Betatown: 9300/30900*100% = 30%

b) Alphatown: 37%
    Betatown:  30%

= Alphatown.

3. This table shows the result of a survey in a factory.

a. What percentage of men are smokers?
b. Compare the percentages of men and women who are non-smokers.

a) 12/76*100% = 16%
b) Men: 64/76*100% = 84%
    Women: 32/41*100% = 78%

11.1 Using Mental Methods

Some percentages are easier to find because they are simple fractions. The purpose of using mental methods is to accelerate working out percentages of simple values.

I have three questions to ease your understanding.
                                                     

Questions:

1. 35% of 84

= 10% + 10% + 10% + 5% = 35%

= 8,4 + 8,4 + 8,4 + 4,2 = 29,4.

2. 49% of 230

= 50% - 1% = 49%

= 115 - 23 = 92.

3.   26% of 78 = 20,28  use this fact to find 52% of $78

You can see that the value that we are working out is the same as the fact which is 78.

The one that we have to focus is the percentage. The fact is 26%. While in the question is 52%.

52-26 = 26%

So first we have to work out the 26 % of 78 and then add the result to the answer in the fact box.

=> 20,28 + 20,28 = 40,56

So the answer is $40,56

Network Topology

Network topology is the arrangement of the various elements such as links and nodes of a computer network. Essentially, it is the topological structure of a network, and may be depicted physically or logically. Physical topology refers to the placement of the network's various components, including device location and cable installation, while logical topology shows how data flows within a network, regardless of its physical design.

Bus Topology

Bus networks (not to be confused with the system bus of a computer) use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

Ring Topology

In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction (either "clockwise" or "counterclockwise"). A failure in anycable or device breaks the loop and can take down the entire network.

To implement a ring network, one typically uses FDDI, SONET, or Token Ring technology. Ring topologies are found in some office buildings or school campuses.

Tree Topology

Tree topologies integrate multiple star topologies together onto a bus. In its simplest form, only hub devices connect directly to the tree bus, and each hub functions as the root of a tree of devices. This bus/star hybrid approach supports future expandability of the network much better than a bus (limited in the number of devices due to the broadcast traffic it generates) or a star (limited by the number of hub connection points) alone.

References: # http://en.wikipedia.org/wiki/Network_topology

# http://compnetworking.about.com/od/networkdesign/a/topologies.htm

The Answer (How Nice Are You?)

Hey guys, these are the answers of the previous questionnaires.

How many a) did you choose?

4~5 a): Congratulation! You are a very nice person! Alhamdulillah. But becareful, bad people like to use a nice person like you for his personal advantage and to deceive you. However, Allah loves a nice person! :)

2~3 a): Cool! You seem to have kindness inside yourself, but perhaps you still have something to encourage you to be more daring to do the right things.

0~1 a): Well... You are not a very nice person. I suggest you to be abetter person. That'll make you feel calmer and happier :)

Thank you for your cooperation!

How Nice Are You?

Hello~ :D
Guys, please help me to finish this project by answering my questionnaires below.

1. If you met a teacher that brings a lot of stuff, would you:

a) Lend him your hands.
b) Greet him and walkway.
c) Pretend you don't see him and walk pass by him.

2. If a suffering dog came to you, would you:

a) Buy or bring some food and to give it.
c) Kick it and go away.
b) Not assume that there's a dog

3. If a person in front you threw rubbish to in appropriate place, would you:

b) Leave it as how it was.
a) Take it and throw it into a rubbish bin.
c) Prefer not to care.

4. If your friend told you that he/she forgot his/her bag, would you:

b) Say "then go take it"
a) Go to upstair and take it for him/her.
c) Ignore him/her.

5. If someone you don't know dropped his/her pen, would you:

a) Pick the pen up and give it to the person
c) Keep doing what you are doing
b) Keep your eyes on the pen until the person pick it up.

Then please report me the result. Just write it on the comment :)
e.g. : 1 b) 2 c) 3 a) 4 b) 5 b)

Click here to see the answers :D

Thanks for your cooperation :)

Choosing the Best Way to Calculate Average

It’s pretty important to choose the best method for finding the average  value or number of a list of values. Remember, there are three divisions of average. They are mode, median and mean. In this session, I would like to explain briefly about choosing the best one from those three to find the average.

Well, they are all useful to find out the average, but sometimes, we found a bit deviated when we use one of them in a typical list of values.

Example:

This is a list of the ages of teachers on a school. Assume I want to find out the average age of the teachers in this school.

Let's try to find out the average age by calculating the mean,

It’s kind of nonsense because only 3 teachers out of 18 who are 26 year old.

So let's try to use median to work out the average age,

24, 24, 24, 24, 24, 25, 25, 25, 25, 25, 26, 26, 26, 27, 27, 27, 27, 39

The middle value is 25. This one is pretty acceptable.

What if we use mode? It’s not really a good one for this case because there are two modes.

So here, we understood that using the median is the most acceptable way to find out the average. 

These kind of problems often happen and we have to be wise enough to choose the best way to calculate the average depends on the type of the statistic.

•  Mean: Use this method to calculate the average when the range is maximum 5.
•  Median: Use this method to calculate the average when the range is too big.
•  Mode: use this method to calculate the average when the range is too big and there is only one mode in the statistic you are working with.

That's all for this session and thank you for your attention :)

Calculating statistics

Calculating Statics

You can use statistics to summarise sets of data and to compare different sets of data.

       You have to be able to calculate mean, mode, median, and range.

   J Mode:  The most common value that appears 

   J Median: The middle value when they are listed in order. 

   J Mean:  The average value of all of the numbers/values.
                          

* Range: The deviation between the largest value and the smallest value.

                      a) Largest value – smallest value

                               

  ü Range is not an average but it measures how spread out a set of values                           or numbers is.

        ü For a large set of data, it’s not practical to list every number separately.                         Instead, you can record a data in a frequency table.

        

      

     

          

             a)    Find the mode.

             b)    Find the mean.

             c)    Find the range.

             a) The mode is 35

           *because the frequency of 35 is 61 which is the highest*

             

              b)    6900 : 200 = 34.5

           *6900 is the sum of all the frenquencies, and 200 is the number of values*

              c) 50 – 25 = 25

           *50 is the largest value while 25 is the smallest value*

                                                                     

That's all for this session and thanks your attention :) 

             

Computer Netwrok

            "A computer network or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. The connections (network links) between nodes are established using either cable media or wireless media. The best-known computer network is the Internet.

Network computer devices that originate, route and terminate the data are called network nodes.^[1] Nodes can include hosts such as servers and personal computers, as well as networking hardware. Two devices are said to be networked when a device is able to exchange information with another device.

Computer networks support applications such as access to the World Wide Web, shared use of application and storage servers, printers, and fax machines, and use of email and instant messaging applications. Computer networks differ in the physical media used to transmit their signals, thecommunications protocols to organize network traffic, the network's size, topology and organizational intent."

               This is a part that explains about the computer network. I took it from wikipedia, thank you wikipedia for the information and new knowledge.

               I think this network is so useful because it really helps us to communicate even if we live far apart. And we also able to exchange data easily, such as using email. By this. we can also gain a lot of knowledge easily. And we can even shop online!! However, since everything has positive and negative, the computer network also have disadvantages as well, such as identity theft, pornography, and we can be addicted to internet that causes us to forget time.

 Guess that's all from me, thank you for your attention :)