Types of Questions Asked in Exams on Percentage

TYPE 1.
If there is increase of X% and subsequently X% decrease then there is always loss / decrease in the condition.
 

Example. If rohan salary is increase by 50% and subsequently decrease by 50%. How much percentage loss?
Ans. By trick ----  50x50/100= 25% decrease/loss 

TYPE 2.
if A is P% more than B. then B is less than by A  with P/(100+P)x100 

Example:  If radha earning is 25% more than sita. Then sita earning is how many percentage less then by radha?

Ans. By trick ---- 25/(100+25)x100=20%   

TYPE 3. 
If A is P% less than B. then B is more than by A with P/(100-P)x100 

Example: If golu age is 20% less than gita than gita age is how many percentage more than golu?
Ans. By trick ---- 20/(100-20)x100=25%

TYPE 4.
If there is p% increase in price . how much % decrease his consumption so that his expenditure on it does not change.
formula P/(100+P)x100

Example. If petrol price increase by 25%. How much percentage a person reduced his consumption so that his expenditure on it does not increase? 
Ans. 25/(100+25)x100=20%

TYPE 5.
if there is p% decrease in price . how much % increase his consumption so that his expenditure on it does not change.
formula P/(100-P)x100

Example. If there is 30% decrease in eggs price. How much a person increased his consumption so that his expenditure on it does not increase?   
Ans. 30/(100-30)x100=42.85

TYPE 6.

Example. If suman need 36% minimum mark to passed a exam but she score 24% mark and fail by 9 marks. What is the total mark? 
Ans. Difference in % = difference in mark

In that 36%-24%=12%
that is 12%=9marks
so, total mark = 9/12x100= 75