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 10% = 10/100 =>1/10 2. 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/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 i. Population after n years = P(1+R/100)^n ii. 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 i. Value of the machine after n years = P(1-R/100)^n ii. Value of the machine n years ago = P/(1-R/100)^n iii. If A is R% more than B, then B is less than A by [(R/100+R)*100]% iv. If A is R% less than B, then B is more than A by [(R/100-R)*100]%
Posted on: Mon, 20 Jan 2014 15:55:20 +0000
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