[Quantitative Aptitude/SBIPO/SSC/CLAT/Placement Drives] - Percentages Tricks

Actually I should have started with this topic only as the concepts from this topic are heavily used in subsequent topics. It also plays a pivotal role in solving Data Interpretation questions.

I won't cover the basics further.Read them from some book and solve some questions.

To convert a fraction/ratio into percentage we multiply it by hundred.

1/2 = 1/2*100 =50 %

To solve percentage questions one must remember some factors as percentages.This is done to make calculations simple.

Explanation: If there is a increase or decrease by a fraction. Let Denominator be the base(original value) and numerator be increase/decrease.Obtain the new value by adding/subtracting the numerator to denominator as per the question.

Next step is to find the Multiplication factor between the Denominator and value given in the question. In this case it is 4 as 7*4=28.Multiply the same factor to the new value obtained and you get the increased/decreased final value.Here 8(New value) * 4 = 32 Ans.



More questions : 

Q. Ramadheer has 33.33 % more guns than Sardar has. By how much percent less guns Sardar has than that of Ramadheer ?

Q. If Faizal increases salary of Guddu by 10 % but then again decreases it by 10 %.What's the net e percentage increase/decrease ?

Sol.

We will see Successive Percentage Increase in Compound Interest topic  

Concept of Product Consistency

Q. Price of a gun in increased by 20 % then by how much percent Sardar should be decrease his use of  guns so that his total expenditure remains the same.

Sol. Price of a gun * Number of Guns = Total Expenditure(Constant)

Gun's price is increased by 20 (P) %  

=> Reduction in use of Guns = P/(P+100) = 20/120=1/6=16.66 %

Now you may proceed and practice questions at :http://www.indiabix.com/aptitude/percentage/017002

Happy Learning :D