Percentages

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Percentages

  1. 1. Percentages T- 1-855-694-8886 Email- info@iTutor.com By iTutor.com
  2. 2. Percentages  Calculating percentage is one of the simplest and most useful of mathematical tricks.  It's one of the simplest ways of quantifying things and presenting comparative ratios.  You will need to know how to calculate percentages as it is a concept used in almost every field where quantification is involved.  Let me first define what percentage means and then explain a simple formula for calculating percentages.
  3. 3. What is Percentage  'Per-Centage' literally means 'per 100 pieces' of anything, which is one way of specifying the fraction of a complete whole.  Simply put, a percentage value is a fraction multiplied by 100.  A portion of the whole; a part.  A way of representing a fraction with the denominator of 100 0.15 100 15 Equals a percentage of 15 So 15% means 15 per 100 (15% of this box is green)
  4. 4. How to Calculate Percentages  Let's say I have a basket of fruits. Out of a total of 20 fruits, 5 are apples, 10 are oranges and 5 are pineapples. Then the percentage of all three fruits in the basket is calculated in the following way.  First determine the 'part' and the 'whole'. Here the 'Whole' is the fruit basket containing 20 fruits and the parts are 5 apples, 10 oranges and 5 pineapples.  Secondly, you must determine the fraction of fruits in basket, that are apples, oranges and pineapples. That is, you must establish the fractions. Here the fractions are:  Fraction of the Apples in Basket = 5/20 =1/4  Fraction of Oranges in Basket = 10/20 =1/2  Fraction of Pineapples in Basket = 5/20 =1/2 So, one can now say that one-fourth of the fruits are apples, half are oranges and another one-fourth are pineapples.
  5. 5.  Once the fraction has been established, calculating percentages is extremely simple.  The percentage of apples in the basket is calculated using following formula. Percentage (%) = (Part/Whole) x 100 Therefore, in the example presented above, Percentage of Apples = 5/20 x 100 = ¼ x 100 = 25% Percentage of Oranges = 10/20 x 100 = 1/2 x 100 = 50% Percentage of Pineapples = 5/20 x 100 = ¼ x 100 = 25%
  6. 6.  Given the whole and the percent, find the part.  Given the whole and the part, find the percent.  Given the percent and the part, find the whole. Calculations with Percents % When the whole and percent are given the part can be found by multiply the percent by the whole Percent x Whole % The percent must be put into decimal form prior to being multiplied, that can be done by dividing the percent by 100 Percent /100 = decimal
  7. 7. Finding a fraction of a quantity Find 4 of 20 5 or 4 × 20 5 Find 1 of 20 5 20 ÷ 5 = 4 So: 4 of 20 is 5 4 4 4× = 16 To do this in one step we can look at the question 4 × 20 5 4 = 16 Divide by 5 and show it by crossing out the 5 on the bottom and cross out the 20 and replace with 4 (the answer to 20 ÷ 5) Example
  8. 8. Example 1: Find 12% of 200 12 × 200 100 2 = 24 cancel common factors Example 2: Find 40% of 270 40 × 270 100 = 108 cancel common factors Example 3: Find 35% of 14 cancel common factors 4 10 ≡ 35 × 14 100 = 4.97 20 ≡ 0.7 Using this method to find percentages of a quantity
  9. 9. The End Call us for more Information: www.iTutor.com 1-855-694-8886 Visit

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