Population Density

Correct answer: B. 200 persons per square kilometre

Explanation: Population density tells us how many people live, on average, in one unit of area. The relevant measure here is arithmetic density, calculated by dividing total population by total area. It does not require any additional information about age, land quality, settlement type, or the distribution of people within the place. The unit will be persons per square kilometre because the area is given in square kilometres.

Use the formula \(Population\ Density=\frac{Population}{Area}\). Substituting the values gives \(40000\div200=200\) persons per square kilometre. Therefore option B is correct. Option A would result from an incorrect division, while options C and D are too large because they do not follow from the stated population and area.

Correct answer: C. 300 persons per square kilometre

Explanation: Answer: C, 300 persons per square kilometre. Use the standard formula: population density = population ÷ area. The calculation is 75,000 ÷ 250. Since 250 × 300 = 75,000, the quotient is 300. Therefore the region has an average density of 300 people per square kilometre. A is not the result of the division. B is the area value and is therefore a tempting but incorrect choice. D is greater than the actual quotient and does not satisfy the calculation. The word average matters: density gives a general ratio for the region, even though some places may be crowded and others sparsely settled. Memory cue: check the answer by multiplying density by area; 300 × 250 returns 75,000.

Correct answer: B. 200 persons per square kilometre

Explanation: Population density is the average number of people living in each unit of area. The standard formula is \(\text{Density} = \frac{\text{Total population}}{\text{Total area}}\). Both numbers must refer to the same region, and the area is measured here in square kilometres, so the final unit is persons per square kilometre. This measure describes concentration, not the exact number in every small part.

Substituting the given values gives \(120000 \div 600 = 200\). Therefore the population density is 200 persons per square kilometre, making option B correct. Choosing 100 would mean dividing incorrectly, while 300 or 600 would overstate the quotient. The result means that if the population were spread evenly, each square kilometre would contain 200 people on average.

Correct answer: B. Region B

Explanation: Population density means the number of people living in one unit of area. When two regions have the same population, the region with less area has more people packed into each square kilometre. A larger area spreads the same population more thinly, so its density is lower.

Let the population be P and the area of region B be A. Region A has area 2A. Thus, density of A is \(P/(2A)\), while density of B is \(P/A\). Since \(P/A\) is twice \(P/(2A)\), region B has the higher density. Therefore, option B is correct. Zero density is impossible because both regions have populations.

Correct answer: A. Region X

Explanation: Population density means the average number of people living in one unit of area, usually one square kilometre. When two regions have equal areas, their densities can be compared directly by comparing their populations. The region with fewer people has fewer people per square kilometre and therefore has the lower density. Since region X has half as many people as region Y, option A, Region X, is correct.

For example, if each region covers 100 square kilometres and Y has 1,000 people, X has 500 people. Their densities are 10 and 5 people per square kilometre respectively. Thus X’s density is half of Y’s density. The equal-area condition is essential; if the areas differed, population alone would not be enough to decide.

Correct answer: A. A large population occupies a small area

Explanation: Population density means the average number of people living in one unit of area, usually one square kilometre. It becomes high when many people are concentrated in a limited area. Therefore, the situation described in option A represents high population density. A large population in a small area produces a large people-to-area ratio, while a small population in a large area produces low density.

The formula is density = population divided by area. If the numerator is large and the denominator is small, the result is large. An uninhabited region has density zero, and a region with zero population also cannot have high density. Thus option A is the only suitable choice.

Correct answer: A. A small population occupies a vast area

Explanation: Population density means the average number of people living in one unit of area, usually one square kilometre. It depends on both population and area. If only a few people live across a very large region, those people are spread out, so the number of people per square kilometre is small. This is why a vast area with a small population gives very low density.

Option A is correct because it directly describes this situation. Option B would give high density: many people are concentrated in a small area. Tall buildings in a metropolis do not by themselves determine density, because density is calculated from population and area. The presence of industries and services may attract people, but it is not the definition or necessary condition of low density.

Correct answer: A. Yes if their areas are different

Explanation: Population density depends on two quantities: total population and the area over which that population is spread. Equal populations do not automatically produce equal densities. A fixed number of people will be more crowded in a smaller country and more spread out in a larger country.

For example, if two countries each have one million people, but one has 10,000 square kilometres and the other has 20,000, their densities are 100 and 50 persons per square kilometre respectively. Therefore, different areas can create different densities, so option A is correct. Birth rate and climate are not required conditions for this conclusion.

Correct answer: A. Yes if their populations are different

Explanation: Yes, two countries can have the same area but different population densities. Density is not decided by area alone; it depends on both population and area. If the areas are equal, the country containing more people will have more people per square kilometre and therefore the higher density. This is exactly the situation stated in option A.

Using density = population divided by area, equal denominators mean that different numerators produce different answers. For example, if equal areas contain 10 million and 20 million people, the second country has twice the density. Rivers or soil may influence settlement, but they are not necessary conditions for the mathematical comparison. Hence option A is correct.

Correct answer: B. 200 persons per square kilometre

Explanation: Population density tells us how many people live in one unit of area. It is found by dividing the total population by the total area. The unit here is persons per square kilometre, so the population and area must be used in the stated units. A larger population in the same area gives greater density, while a larger area for the same population gives lower density.

Using the formula, density = population ÷ area. Thus, density = 300000 ÷ 1500 = 200 persons per square kilometre. Therefore, option B is correct. The value 100 would result from an incorrect division, while 300 and 450 are also not obtained from the given population and area. The calculation shows that, on average, 200 people live in each square kilometre.

Correct answer: C. 300 persons per square kilometre

Explanation: Answer: C, 300 persons per square kilometre. To find density, divide the total population by the total area. Thus density = 45,000 ÷ 150. We can simplify the calculation by removing one zero from both values: 4,500 ÷ 15 = 300. Hence the correct ratio is 300 people for every square kilometre on average. A repeats the area value and is not the quotient. B is too low, while D is too high. A density answer must include the unit persons per square kilometre because it expresses a relationship between people and land. Memory cue: if the same population is placed in a smaller area, density becomes higher; always use population over area.

Correct answer: C. 300 persons per square kilometre

Explanation: Answer: C, 300 persons per square kilometre. Apply density = population ÷ area. Therefore, density = 240,000 ÷ 800. Cancelling two zeros gives 2,400 ÷ 8 = 300, so the average density is 300 persons per square kilometre. Option A is too low, B results from an incorrect division, and D is too high. The answer is not 800 because 800 is the area, not the number of people per unit area. A useful check is multiplication: 300 × 800 = 240,000, which reproduces the given population. Density is an average ratio, so it does not imply that every square kilometre has exactly the same number of residents. Memory cue: for large numbers, cancel common zeros before dividing, but retain the correct unit.

Correct answer: A. Because density is based on the ratio of population to area

Explanation: Population density is not simply the number of people in a place. It expresses the relationship between the population and the amount of land available, usually as people per square kilometre. The same population can produce very different densities in a small region and a large region. For this reason, area is an essential part of both the meaning and the calculation of density.

The relevant formula is \(\text{density}=\frac{\text{population}}{\text{area}}\), so option A is correct. Area alone cannot tell us total population, because two places with equal area may have different populations. Area also does not directly give birth or death rates; those are demographic rates calculated from births or deaths and a population base. Hence B, C, and D confuse different measures.

Correct answer: A. An inaccessible region with harsh climate

Explanation: Population density is the number of people living in a unit of area. Regions with very harsh climates, such as extreme cold, heat, or dryness, often make settlement and farming difficult. Inaccessible mountains, deserts, polar areas, or remote regions also have higher transport costs and fewer regular economic opportunities. These physical and economic barriers usually lead to fewer permanent residents per square kilometre.

Option A is correct because difficult climate and accessibility discourage dense settlement. A fertile irrigated plain can support intensive farming and many inhabitants, while an industrial centre and an important port usually offer jobs, services, and transport links that attract people. These alternatives may not always be densely populated, but they are generally more favourable than harsh, inaccessible regions. Therefore the safest general answer is an inaccessible region with a harsh climate.

Correct answer: A. Metropolitan region with jobs and services

Explanation: Metropolitan regions often attract many people because they contain varied economic and social opportunities. Jobs may be available in industries, offices, trade, transport, education, health care, and other services. Roads, public transport, markets, utilities, and institutions also make daily life and business easier. These factors can support a large population within a limited area and produce high density.

Therefore option A is correct. Permanent ice, waterless deserts, and very high uninhabited mountain peaks usually impose severe limits on water supply, farming, transport, construction, or comfortable living. They generally have very low density, although small settlements can exist in some difficult environments. The word “often” matters: not every metropolitan area is equally dense, but compared with these naturally harsh and uninhabited regions, it is much more likely to have high population density.

Correct answer: A. No it gives only average concentration

Explanation: Population density is an average measure. It is calculated by dividing the total population of a region by its total area, usually expressed as persons per square kilometre. Because it combines information for the whole region into one number, it cannot show the precise location of every person or settlement. A region may have a moderate average density even when most people live in one city and large areas are almost empty.

Option A is therefore correct: density shows average concentration, not the exact internal pattern of settlement. Options B and C incorrectly treat density as a detailed location record, while D wrongly limits it to a city map. A population distribution map or settlement survey would be needed to show where people are actually located within the region.

Correct answer: A. Yes because average density can hide local differences

Explanation: Average population density is a broad national measure. It is found by dividing the total population of a country by its total area. Because the country may contain deserts, mountains, forests, or other sparsely settled spaces, this average can be low even when particular urban locations contain many people in a small area.

Thus, a few cities can have very high local density while the national average remains low. Option A is correct because an average combines very different places and can hide those local contrasts. The other choices incorrectly claim that this situation is impossible or requires unrealistic conditions. Density should therefore be compared at the appropriate scale, such as city, region, or country.

Correct answer: B. 200 persons per square kilometre

Explanation: Population density tells us how many people live, on average, in one unit of area. It is found by dividing the total population by the total area. The unit here is persons per square kilometre, because the area is given in square kilometres.

Using the formula, density = population ÷ area = \(10000 \div 50 = 200\) persons per square kilometre. Therefore, option B is correct. Options A, C, and D result from using an incorrect division or scale. This does not mean exactly 200 people live in every small part; it is an average for the whole region.

Correct answer: C. 200 persons per square kilometre

Explanation: Population density tells us how many people live, on average, in one unit of area. It is found by dividing the total population by the total land area. The unit here is persons per square kilometre, so the answer must show both the number and the area unit. A larger population in the same area gives higher density, while a larger area for the same population gives lower density.

Use the formula \(\text{density}=\frac{\text{population}}{\text{area}}\). Thus, \(160000\div800=200\). The density is therefore 200 persons per square kilometre, which matches option C. Option A would result from an incorrect division, while option D is twice the correct value and may arise from a calculation error. The correct operation is division, not subtraction or multiplication.

Correct answer: B. Density will double

Explanation: Density compares population with the area occupied by that population. It is calculated as population divided by area. If the area does not change, the denominator remains fixed. Consequently, changing the population changes the density in the same direction and by the same proportion. Doubling the population therefore doubles the number of people represented in each square kilometre on average.

For example, if the original density is \(P/A\), after the population doubles it becomes \(2P/A = 2(P/A)\). Thus the new density is twice the original density, so option B is correct. It will not become half or zero, because neither the population is being reduced nor the area removed. It also cannot remain unchanged when the numerator doubles but the denominator stays constant.

Correct answer: B. It will become half

Explanation: Answer: B, density becomes half. The formula is density = population ÷ area. Suppose the original population is P and the original area is A; original density is P/A. If the population remains P but the area becomes 2A, the new density is P/(2A), which equals half of P/A. The same number of people is now spread over twice as much land, so there are fewer people per square kilometre on average. A is wrong because doubling the area does not double density when population is fixed. C is wrong because the denominator has changed. D is also incorrect and reverses the relationship. This conclusion assumes that the population really stays constant. Memory cue: with population fixed, density and area move in opposite directions—double the area, halve the density.

Correct answer: A. Density has halved

Explanation: Population density tells us how many people live in one unit of area, such as one square kilometre. To compare a change, divide the new density by the original density. Here the original value is 400 and the new value is 200. Since 200 is exactly one-half of 400, the density has halved. Therefore, option A is correct. This does not mean that the population must always have halved; the area could also have changed.

The calculation is \(200\div400=0.5\), or 50 percent of the original density. Thus, the decrease is 50 percent, and the remaining density is half the starting value. A doubling would require the new value to be 800, while no change would require it to remain 400. The wording asks about the density itself, so the direct comparison clearly supports option A.

Correct answer: B. Density doubled

Explanation: Population density tells us how many people live, on average, in one square kilometre. When the density changes from 150 to 300 persons per square kilometre, the new value is twice the old value. This means that the number of people per unit of land has doubled. Density itself does not tell us whether the change happened because population increased, area decreased, or both changed.

To check the result, divide the new density by the old density: \(300\div150=2\). Thus, the density is two times, or double, its original value. It has not become three times, because \(3\times150=450\), and it has not remained unchanged. Therefore, option B is correct.

Correct answer: A. Greater concentration of people per unit area

Explanation: High population density generally indicates that many people are concentrated within each unit of area. It describes the relationship between population and space, not the total size of the region. Thus option A correctly explains the meaning of high density. A dense area may be small or large; what matters is how many people occupy each square kilometre.

The measure is calculated as population divided by area. A larger result means more people are present in the same unit of space. High density does not mean that a place is uninhabited, that its total area must be very large, or that its birth rate is zero. Those statements confuse density with other population or geographical facts. Therefore option A follows directly from the definition.

Correct answer: A. Fewer people living per unit area

Explanation: Low population density means that relatively few people live in each unit of area on average. It describes the relationship between population and area, not necessarily the total number of people in the whole region. Therefore option A, fewer people living per unit area, is the correct interpretation.

A large region may have a very large total population but still have low density if its area is enormous. In contrast, a small region may have a smaller total population but high density if many people are concentrated in limited space. Options B, C, and D are not correct: B describes high density, while C and D make claims about total population or area that do not necessarily follow from density alone.