Percentage Aptitude Questions and Answers for all competitive exams preparation for freshers and experienced pdf free download

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1. 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, 48% = 48 / 100 = 12 / 25.
=> To express a / b as a percent :
We have a / b = (a / b × 100)%.

2. If the price of a commodity increases by R%, then the reduction in consumption so as not to increase the expenditure is :
[R / (100 + R) ×100]%.
=> If the price of a commodity decreases by R%, then the increase in consumption so as not to decrease the expenditure is :
[R / (100 - R) ×100]%.

3. Results on Population :

Let the population of a town be P now and suppose it increases at the rate of R% per annum, then :
=> Population after n years = P(1 + R / 100 )ⁿ.
=> Population n years ago = P / (1 + R / 100)ⁿ.

4. Results on Depreciation :

Let the present value of a machine be P. Suppose it depreciates at the rate of R% per annum. Then :
=> Value of the machine after n years = P(1 - R / 100)ⁿ.
=> Value of the machine n years ago = P / (1 - R / 100)ⁿ.