PERCENTAGE- IMPORTANT FORMULAS
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- Concept of Percentage:By a certain percent, we mean that many hundredths.Thus, x percent means x hundredths, written as x%.
To express x% as a fraction: We have, x% = x . 100
Thus, 20% = 20 = 1 . 100 5
To express a as a percent: We have, a = 
a x 100 
%.b b b
Thus, 1 = 1 x 100 %= 25%. 4 4
- Percentage Increase/Decrease:If the price of a commodity increases by R%, then the reduction in consumption so as not to increase the expenditure is:
R x 100 
%(100 + R)
If the price of a commodity decreases by R%, then the increase in consumption so as not to decrease the expenditure is:R x 100 %(100 - R)
- Results on Population:Let the population of a town be P now and suppose it increases at the rate of R% per annum, then:
1. Population after n years = P 1 + R n 100
2. Population n years ago = P 1 + R n 100
- Results on Depreciation:Let the present value of a machine be P. Suppose it depreciates at the rate of R% per annum. Then:
1. Value of the machine after n years = P 1 - R n 100
2. Value of the machine n years ago = P 1 - R n 100
3. If A is R% more than B, then B is less than A by R x 100 %.(100 + R)
4. If A is R% less than B, then B is more than A by R x 100 %.(100 - R)
This post was written by: Rajendra Prasad
Rajendra Prasad is a professional blogger, web designer and front end web developer. Follow him on Facebook
