Problems Based on Population

Overpopulation causes a lot of problems. Reasons of overpopulation are poverty, increased birth rate, immigration, child labor, fertility treatments, and better medical facilities reduce death rates, lack of resources, etc. The population is increasing rapidly all over the world and especially in India. At the increasing rate of 1.07% per year, the global world population is expected to be more than 8 Billion till 2030. The current average population is more than 80 million per year. Big families with more than 5 members are resulting in poverty in developing countries like India. Today in this article, we are going to cover some quantitative aptitude questions related to the population problem.

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Population Problem

Population problem is an ever-growing phenomenon. Every year you see an increase in it. This increase is calculated by using percentage. The population problem is an ever-growing phenomenon. Every year you see an increase in it. This increase is calculated by using percentage. There are many tricks and methods to calculate the changes being done in it. We will try and cover every different type of question-based on it. We will also provide some questions for you to practice at the end.

Population problem

Example Based on Population

Q. The population of New Foundland increases at a uniform rate of 8 % per year, but due to people flying from different countries there is a further increase in it by 1 %. This 1 %, is the increase in population which is to be calculated on it after the 8 % increase and not on the previous year’s population. Find what the amount of percentage increase of population after 2 years.

A. 19.76
B. 17.91
C. 18.081
D. 18.24

Answer: Here, you need to find an increase in the percentage of the population after two years. But there is a condition given where a 1 % increase is only when there was an 8 % increase and not before that. Thus 1 % increase will only be calculated after there is an increase of 8%. This means that for 2 years, we will only calculate this increase two times.

For the first years let’s suppose that the population before was 100. Now, with the increase of 8%, the new population after one year will 108. Now, there is a one percent increase in this population. So, 1% of 108 is 1.08. So, new population will be 108 + 1.08 = 109.8. The important thing here to note is that you have to take 8% and 1% separately. You cannot take a 9% increase in the population. Because then the new population after one year would have been 109 instead of 109.8.

Now, for the second year, there is again an increase of  8% in the population. So, the population after two years will be 8% of 109.8 which will be 8.78 => 109.8 + 8.78 = 118.58. Increasing 118.58 by 1% we get new population as 119.76 which is our required answer. So, the increase in population after two will be 19.76 %.

Example Based on Voters

Q. It was decided that 800 people will vote in the elections. But out of 800, 1/3 of the people were sick. The people in the opposition party managed to increase their strength somehow by 100 %. The resolution was rejected by the majority. This majority was 50 % of that by which it would have been passed if none of these changes would have occurred. How many people in Vadodara finally voted for the resolution and against the resolution?

A. 150 (for), 300 (against)
B. 200 (for), 400 (against)
C. 200 (for), 300 (against)
D. 100 (for), 200 (against)

Answer: This type of questions will easier to solve if you do it through options. We will go through the options one by one and see what is the correct answer. In the first option, there 150 for and 300 against. So 350 people are remaining. This 350 have rejected the resolution. But this is not possible because 1/3 of the people were sick. And 1/3 of 500 is 160+. But here it is mentioned that 150 people voted for. So option A is not the correct answer.

For option B, 200 people voted for and 400 voted against. So 200 people rejected the resolution. So if none of this thing would have happened than the resolution would have been passed by 400 people which are 600 for and 200 against. 1/3 people were sick. So, 200 were sick and opponents doubled their vote from 200 to 400. So, option B is the correct answer.

Practice Questions

Q. Of the total number of people in Vadodara, 25 % of men and 45 % of women are married. What is the total percentage of the population of adults is married? (Assume that no women marry more than one man and vice versa).

A. 31.1 %
B. 32.3 %
C. 32.14 %
D. 33.33 %

The correct answer is C.

Q. The population in Ahmedabad was 3000. It was increased by 4 % in the first year and then it was decreased by 3 % in the next year. What was the total population at the end of two years?

A. 3208
B. 3028
C. 2028
D. 3026

The correct answer is D.

Q. Every year the population in India grows at the rate of 20 %. If the population in 2010 was 50000 then what will be the population of India in 2013?

A. 88000
B. 86000
C. 86200
D. 86400

The correct answer is D.

Q. The population of Denver in 2015 was 160000. After one year there was a decrease in population of 6 %. After that, there was an increase in population by 8 %. What was the population of Denver in 2017?

A. 162422
B. 162432
C. 163422
D. 165432

The correct answer is B.

Q. In a town 30 % were children, while 45 % were men. 25000 people in the town were women. What is the total number of men and children in the town?

A. 65000
B. 75000
C. 85000
D. 90000

The correct answer is B.

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One response to “Percentage Change”

  1. kiran says:

    Total wrong teaching and examples are wrong change the mistakes of every example, I found this
    change in percentage = 4/40 x 100 = 20%.

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