In this article, we provide you a short and effective summary for Percentages. We cover a list of 15 formulas and short-cuts that you can use for Percentage questions. The following is a list of important formulas for Percentage:
1. Percent implies “for every hundred”.
% is read as percentage and x % is read as x per cent.
2. To calculate p % of y
(p/100) x y = (p x y)/100
p % of y = y % of p
3. To find what percentage of x is y: y/x × 100
4. To calculate percentage change in value
Percentage change = {change/(initial value)} x 100
5. Percentage point change = Difference of two percentage figures
6. Increase N by S % = N( 1+ S/100 )
7. Decrease N by S % = N (1 – S/100)
8. If the value of an item goes up/down by x%, the percentage reduction/increment to be now made to bring it back to the original point is 100x/ (100 + x) %.
9. If A is x% more /less than B, then B is 100x/(100 + x) % less/more than A.
10. If the price of an item goes up/down by x %, then the quantity consumed should be reduced by 100x/ (100 + x)% so that the total expenditure remains the same.
11. Successive Percentage Change
If there are successive percentage increases of a % and b%, the effective percentage increase is:
{(a + b + (ab/100)}%
12. Percentage – Ratio Equivalence:
N is Numerator
D is the Denominator
13. Product Stability Ratio:
A × B = P
If A is increased by a certain percentage, then B is required to be decreased by a certain percentage to keep the product P stable.
Expressing the percentage figures in ratios:
Percentages: The Complete Lesson
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