Percentage calculation on population Shortcut Tricks
We all know that the most important thing in competitive exams is Mathematics. It doesn’t mean that other topics are not so important. But only math portion can leads you to a good score. Only practice and practice can give you a good score. You should do your math problems within time with correctness, and only shortcut tricks can give you that success. But it doesn’t mean that without using shortcut tricks you can’t do any math problems. You may do math problems within time without using any shortcut tricks. You may have that potential. But so many other people may not do the same. Here we prepared percentage calculation on population shortcut tricks for those people. Here in this page we try to put all types of shortcut tricks on Percentage calculation on population. But we may miss few of them. If you know anything else rather than this please do share with us. Your help will help others.
Percentage is a very important chapter and it uses most chapters for calculation.Shortcut Tricks is based on, to find the population of a particular town,city in increased and decreased order that is obtain in this type of questions.
we go through the shortcut tricks. This type of problem are given in Quantitative Aptitude which is a very essential paper in banking exam.Under below given some more example for your better practice.
when we say 100 percent in mathematical notation we write 100% so, 35 % means 35 per 100 and 65% means 65 per 100 it is a proportion per hundred and it is used to find marks percentage of a student, profit percent or loss percent of a particular product.
It is also used in find out the depreciation at the rate percent per annul or population of a particular city or town where due to some reason rate of population increases or decreases.
we can expressed ration number as percent, Here is some different percent related problems are given with shortcut tricks below.
Example 1:
The population of a town has rapidly increases by 20% every year. If the population of the town in 2011 was 6,00,000 than, What would be its population in 2014 ?
Answer: Population in that town in 2014
600000 x 120 x 120 x 120 / 100 x 100 x 100 = 1036800.
Example 2:
In a town has present population 52500 and If it is decreased by 20% per annul. What would be the population its 2 years hence.
Solution:
We know
Population after n year = P(1+R/100)n
So, Here we
P = 52500
R=20% ( decreased )
n = 2 years.
Population after 2 years
Short Tricks :
= 52500 x 80/100 x 80/100
= 33600.
Example 3:
The population of a city was 2 years ago 24000, population decreases every year at the rate of 5 %. Find the present population of the city.
Solution :
population was decreases at a particular rate so
Present population of that city is
=24000 x ( 1 – 5 %)2
=24000 x ( 1 – 5 / 100)2
=24000 x ( 19 / 20 x 19 / 20 )
=21660.
Example 4:
The population in pune city was 1,50,000 three years ago. If it increased by 4%, 5% and 6% respectively in the last three years , then Find the present population of the pune city.
Solution :
Here population increased by continuous three years respectively, So Present population is the city is
=150000 x (1 + 4 / 100 )( 1 + 5 / 100 )( 1 + 6 / 100 )
= 150000 x 104 / 100 x 105 / 100 x 106 / 100
= 150000 x 52 x 21 x 106 / 50 x 20 x 100
=173628.
Example 5 :
60% of the population of a city are men and 15% are women. If the number of children are 20000, then the number of men will be of that city ?
Answer :
25% = 20000
60% = 20000 x 60 / 25 = 48000 .
Example 6 :
The total population of a village is 6000. The number of males and females increases by 10% and 20% respectively and consequently the population of the village becomes 7500. What was the number of males in the village ?
Answer :
The total % increased population
= 7500 – 6000 x 100 / 6000
= 1500 x 100 / 6000 = 25%
By allegation method
Male Female
+10 +20
. +25
5 15
Male population before increment
= 6000 x 5 / 20 = 1500
Example 7:
The population of a town is 56600. If in a 1st year it is decreased by 10% and 2nd year it is increased by 20%. What would be the population of that city after 2 years?
Answer :
Shortcut tricks :
56600 x 90 x 120 / 100 x 100 = 61128
So, after 2 years the population of that city is 61128.
Example 8 :
The population of a city increases by 10% annually. If its population in 2010 was 12000 then, What it was in 2007 ?
Solution :
We need to find the population of city 3 years back, and also the population of a city increases by 10% annually.
So, the population of city was in 2007
=12000 / (1 + 10%)3
=12000 x ( 22 / 20 x 22 / 20 x 22 / 20 )
= 15972.
Example 9:
If in a city every year population is decreased by 6%, What would be after 2 years of this towns population while its present population has 65000.
Answer: 65000 x 94 x 94 / 100 x 100 = 57434.