Percentage questions play a very important role not only in exam but in our daily life also. Though the percentage is used is many maths aptitude topic, we study it as a separate unit due to its importance by the exam point of view. Strong command over percentage indicates the strong command over half of maths aptitude. Percentage questions are quite confusing for many people. Whenever we try to solve percentage questions by using pen and paper they become even more time taking.
Hence to overcome this problem we are sharing some of the best maths trick to solve percentage questions just in 2-3 seconds.
Let us understand type 1 of Percentage Questions with an example:
Question: If salary of A is 50% greater than the salary of B. So how many lesser the salary of B than the salary of A ?
Solution using our short trick:
Let always suppose the salary of B = 100.
Note:
- If salary of A > B then Add (+) the greater percent of salary of A in salary of B.
- If salary of A < B then subtract (-) the lesser percent of salary of A from salary of B.
As given in the question salary of A is 50% greater than salary of B,
So,
Salary of A = 100 + 50 = 150
Now we know that salary of B is ’50’ less than the salary of A which is ‘150’.
So,
This is the required answer.
Shortest Trick for this type of Percentage Questions:
Below we are sharing some some standard combination of results (सीधे याद रखने योग्य परिणाम). A total of 90% of questions in exams asked from this topic (type 1) are from those results directly. If you remember those results you will not even take a second to tick the answer:
100% and 50% or (100)% and (100/2)%
50% and 33.3% or (100/2)% and (100/3)%
33.3% and 25% or (100/3)% and (100/4)%
25% and 20% or (100/4)% and (100/5)%
20% and 16.66% or (100/5)% and (100/6)%
उदाहरण:
- यदि A की सैलरी B की सैलरी से 100% ज्यादा है तब B की सैलरी A की सैलरी से (100/2)% या 50% कम होगी.
- यदि A की सैलरी B की सैलरी से (100/2)% या 50% ज्यादा है तब B की सैलरी A की सैलरी से (100/3)% या 33.33% कम होगी.
- यदि A की सैलरी B की सैलरी से (100/3)% या 33.33% ज्यादा है तब B की सैलरी A की सैलरी से (100/4)% या 25% कम होगी.
- यदि A की सैलरी B की सैलरी से (100/4)% या 25% ज्यादा है तब B की सैलरी A की सैलरी से (100/5)% या 20% कम होगी.
- यदि A की सैलरी B की सैलरी से (100/5)% या 20% ज्यादा है तब B की सैलरी A की सैलरी से (100/6)% या 16.66% कम होगी.
इसी प्रकार:
- यदि A की सैलरी B की सैलरी से (100/2)% या 50% कम है तब B की सैलरी A की सैलरी से (100)% या 100% ज्यादा होगी.
- यदि A की सैलरी B की सैलरी से (100/3)% या 33.33% कम है तब B की सैलरी A की सैलरी से (100/2)% या 50% ज्यादा होगी.
- यदि A की सैलरी B की सैलरी से (100/4)% या 25% कम है तब B की सैलरी A की सैलरी से (100/3)% या 33.33% ज्यादा होगी.
- यदि A की सैलरी B की सैलरी से (100/5)% या 20% कम है तब B की सैलरी A की सैलरी से (100/4)% या 25% ज्यादा होगी.
- यदि A की सैलरी B की सैलरी से (100/6)% या 16.66% कम है तब B की सैलरी A की सैलरी से (100/5)% या 20% ज्यादा होगी.
1-Questions based on increase
A-Ram^s income is 20% more than shyam^s income.What % shyam^s income is less than Ram^s income?
Solution- Shyam^s income % less than Ram^s income = 100*20/120= 50/3%.
B- By a reason a man increases his expenditure by 40%.After end of that reason by how much % will be diminish his expenditure so that his expenses remain the same?
Solution- %decrease in expenditure = 100*40/140= 28.57%.
2- Questions based on decrease
A- The piece of sugar falls by 20% by how much percent should a consumer increase its consumption so that his expenditure remains unchanged?
Solution- % increase = 100*20/80 = 25%.
B- on multiplication of two numbers one number has decreased by 30% . How much % should the second number be increase so that the product be correct?
Solution- % increase of second number = 100*30 = 259/7%.
3- Questions based on decrease and increase both
A- Mohan decreased 15% his expenses and later on decreased by 5% more.How many % did his expense decrease?
Solution- percent change= -15-15+{-15*-15}/100= -19.25 % decrease.
B-The price of an article is reduced by 25% and it^s daily saly increased by 30%.Find the net % effect on daily sale?
Solution- percent change = -25+30+{-25*30}/100= 2.5 % decrease.
A- The radius of a circle is reduced by 5%. Find the % reduce in the area of circle?
Solution- % change in area -5-5+0.25 = -9.75%.
B- If the diameter of a sphere is increased by 20% . By what% is its surface area increased?
Solution- % change in surface area = 20+20+400/100= 44%.
5- Question based on volume
A-Radius of a cylinder is 5% icreased and height is increased 10% .Find the % increase in volume of the cyinder?
Solution- % increase in two dimensions = 5+5+25/100=10.25% increase
% increase in three dimensions= 10.25+10+1.025 = 21.275% increase.
B- Diameter of a sphere is reduced by 10 % . By what % did its volume reduce?
Solution= % reduce in two dimensions= -10-10+1= -19% decrease
% increase in three dimensions = -19-10+1.9= -27.1% decrease.
6- Questions based on income and expense
A- gopal spends 30% of his income on grossery and 40% of remaining on travels. After this he spends 25% on education . If his annual income is rs. 2lakh.Find his annual savings?
Solution- Gopal^s saving = 200000*70/100*60/100*75/100 = 20*7*6*75 =63000.
B- A man spends 30 % of his income on education , 50% of remaining on ration. He gives rs-1000 for house rent from remains. At last he saves rs- 1800. Find the mans monthly income?
Solution- Let mans monthly income is rs- X
X*70/100*50/100-1000= 1800
7x/20= 1000+1800=2800
So x= 2800*20/7= rs. 8000.
7-Question based on Population
A-The population of a town is 100000 it increases 10% per annum what will be
its population of the 3 years?
its population of the 3 years?
Solution- 100000[110/100]3= 100000[11/10]3
100000*1331/1000=133100.
B-The population of mohans village is 6760 if it increases by 4 per present yearly then how much was the
population before 2 years?
population before 2 years?
Solution-6760 = P*676/625
P= 6760*625/676= 6250.
8- Question based on fail and pass in exam
A-In an examination 60% student passed in mathematics 70% in English and 50 % I both subjects . what find the percentage of total who passed in both subjects?
Solution-% passed of students = 100-40-30+50= 150-70= 80 .
B-There were two papers in an examination of Hind,i 75% students in first paper, 55 and 35 per students in both the paper were failed. how many% student failed?
Solution- % passed students = 100-25-45-=35=135-70=65%
So % of failed students = 100 – 65 = 35 %.
9- Miscellaneous questions
A- In a hostel 800 boys live. 75% of the boys play hockey and 50% play football.Each boy plays either hockey or football or both . how many boys play the both game?
Solution-let x boys play the both games
So 800= 75 % of 800 + 50 % of 800 – x
So 800 = 600 + 400 – x
X = 1000-800 = 200
B-In an office 70% employees like tea and 40% like coffee. Each employee likesanyone or both . if 25 employees like both then how many employees are in theoffice?
Solution – Let there are X employees In the office
X= 70 % of X + 40 % of X-25
X = 70/100 * X + 40/100 * X – 25
X=7x/10+4x/10 – 25
X = 11x/10 – 25
11x/10 –x = 25 = 11x – 10x/10 = 25
So x/10 = 25 or x = 250.
Questions asked in ssc cgl examinations:
1-The length of a rectangle increase by 12% and the breadth by 10 % then the % increase in area? [ssccgl 2012]
2- A number is increased by 20 % and the decreasd by 20 % . Finally the number is ?[ssc 2014]
3- Ratan expenditures and savings are in the ratio 5 : 1. If his salary is increased by 25 % and saving by 15 % the percentage of increase in his expenditure is ? [ssc cpo 2012]
4- If a gets 25 % more than b and b gets 20 % more than c , then the share of c out of a sum of 740 is ? [ssc tax assistant 2009]
5- Out of total population of 5000 people in a village men increased by 10% and women by 15 % .Now the total population becomes 5600 in a year . the women population in the village is originally ? [cpo si 2012].
6- The population of a town has been increasing at the rate of 10% every year . The present population is 121000. What was the population two years ago? [ssc tax assistant 2009]
7- Three fifth of two third of three seventh of a number is 150 . what is 60 % of tha number ?
8- A student scored 32 % marks in science subjects out of 300. How much should he score in
language papers out of 200 if he is to get overall 46 % marks? [ssc cgl 2013].