"Percentage."

Introduction:

Percentage is a Special kind of fraction in which the denominator is 100. It is expressed using the percentage symbol i.e, "%". For example if we have to convert 3/8 into equivalent fraction with denominator 100, we can find the percentage as follows,
So the 3/8 of 100 can be: 3/8 ´ 100 = 300/8 = 37.5
Percents and hundredths are same. And we can easily make conversions between the two.
For example .65 = 65 hundredths = 65%
This can be done with reverse.
34% = 34 hundredths = 0.34

Simple Conversions & Estimations:

§ 100% of any number is that number.
100% of 2 is 2.
§ 50% of that number is half of that number.
50% of 2 is 1.
§ 25% of that number is one forth of that number.
25% of 2 is 0.5
§ 1% of that number is one tenth of that number.
1% of 2 is 0.2

Using these conversions we can estimate about percents.

Examples:

1) Estimate what percent is 29 of 120.
Now because we are making rough estimations so we can round off 29 to 30.So 29/120 becomes 30/120.30 / 120 = 1 / 4 = 0.25 = 25%.

2) What is 12% of 70.Clearly twice 12% is 24% which is very close to 25% = 1 / 4.So we can multiply the 25% and 1 / 4 with 1 / 2 (by half because 12% is approx half of 25%) for estimation of 12%.25% x 1 / 2 = 1 / 2 x 1 / 4 = 12.5% = 1 / 8.Now 1 / 8 x 70 = 8.75,whish is 2% of 70.

3) If I give you a square made up of 100 small squares and ask to shade 1/3 of it(i.e. 1/3 of hundred boxes),what will you do?
Now you have to find 1/3 of 100,as follows,
1/3 of 100 =
(100 ´ 1)/3 =
100/3 =
33.33
What you have done? You have found that one third of hundred is 33.33%.

Percentage Usage:
Percentage calculation is used in various fields. We find interest using percentage.

· Interests:
Interests is the amount we pay when we take a financial loan. This amount of money is usually decided in percentage. The amount of money taken is called principal money.
This interest can be of two types simple and compound.
Example:
If a bank charges 5% as interest on each $100.What will be the amount of interest paid for this rate?
The 5% of 100 is 5, so $5 will be paid for each $100.

In simple interest the interest is taken on the principal money only, for the duration of loan. In this case we usually find the amount of interest for one year and then multiply with the number of year the loan is taken.

Example:
If a bank charges 7% interest on $1000 loan. And this loan is taken for three years.
What will be the total amount of interest paid?
Now 7% of 1000 is 70. And loan is taken for three years. That is 70 + 70 + 70 = 210.So a total of $210 will be paid as interest.

The compound interest is made if there is some previous amount of interest left and more interest is taken as loan.

Example:
A bank charges 9% on $800 loan.This loan is taken for three years.How much it will cost the borrower?
First year this will cost:
9% of 800 is 72.
Second year it will cost:
800 + 72 = 872.9% of 872 is 78.48
Third year it will cost:
872 + 78.48 = 950.48.So 9% of 950.48 is 85.54
So the total amount paid as interest in three years is:
72 + 78.48 + 85.54 = $236.02

· Sometimes we also need to know the percent increase or decrease in an amount.

Example:

1) A sales person sells 1200 toys every month. How many more toys he must sell if he wants to increase his sales by 8%?
8% of 1200 is 150.So he must sell 150 more toy to attain his goal.

2) A nutritionist advice a heart patient to take a special bread which has 6 grams of fat per slice than ordinary bread which has 10gram of fat per slice. To what percent the fat is decreased?
The change is 10g - 6g = 4g, a decrease of 4 grams; since 4 grams is 40% of 10, we can say that the patient is taking a bread which has 40% less fat in it.

· The percentage is also used in business.

Examples:

A & B invested in a business. A invested 45% and B invested 55%. If they had a profit of $8000. Find share of each in the profit.
A's share = 45/100 ´ 8000 = 3600 $
B's share = 55 /100 ´ 8000 = 4400 $

· Commissions, on sale products is also calculated in percentage most of the time.

Example:

If a property agent helps Jack to sell his agriculture land for $6000. And it was decide that the agent will be paid 5% of the amount. What is the amount the agent will get?
Total price = $ 6000
Agent's share = 5 /100 ´ 6000 = 300
So the agent will get 300$.

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