Population Growth

Correct answer: A. \(0.5\%\)

Total population growth rate is the sum of natural increase and net migration: \(1.2\% + (-0.7\%) = 1.2\% - 0.7\% = 0.5\%\). So the total growth rate is \(0.5\%\).

Correct answer: B. 1.0 percent

Total population growth combines natural increase with net migration. Natural increase is calculated as birth rate minus death rate: \(28-12=16\) per thousand. Net migration is negative 6 per thousand, meaning 6 more people per thousand leave than enter. Therefore total growth is \(16+(-6)=10\) per thousand. Since 1 per thousand equals 0.1 percent, 10 per thousand equals \(1.0\) percent.

Option B is correct. The negative migration rate must be subtracted from the natural increase, rather than added as a positive number. Option A would correspond to only 6 per thousand, option C would incorrectly treat the natural increase as the final percentage, and option D would ignore the negative migration effect or combine values incorrectly. Thus the country’s total growth rate is a positive 1.0 percent.

Correct answer: A. First region

Percentage growth compares the increase with the original population, not merely the number of people added. The formula is \(\text{percentage growth}=\frac{\text{increase}}{\text{original population}}\times100\). This allows fair comparison between regions of different sizes. A larger absolute increase does not necessarily mean a larger percentage increase.

The first region increases by 0.5 million from 5 million, so its growth is \(\frac{0.5}{5}\times100=10\%\). The second increases by 1 million from 20 million, so its growth is \(\frac{1}{20}\times100=5\%\). Therefore option A, the first region, has the higher percentage growth. Area is not needed for this comparison because the question asks about population growth percentages.

Correct answer: C. Positive 2 per thousand

Natural increase is the difference between the birth rate and the death rate. If deaths exceed births by 3 per thousand, the natural increase is \(-3\) per thousand. Net migration is positive 5 per thousand, meaning that immigration exceeds emigration by 5 per thousand. Total population change combines both components: \(-3+5=+2\) per thousand.

Therefore, option C is correct: the total growth rate is positive 2 per thousand. The positive migration more than compensates for the natural decrease. Option B would ignore the migration contribution, while A incorrectly adds the magnitudes of two effects that act in opposite directions. Zero would occur only if positive migration exactly balanced a natural decrease of 5 per thousand. The supplied answer and calculation are correct.

Correct answer: C. 70 years

The Rule of 70 gives an approximate doubling time by dividing 70 by the annual growth rate expressed as a percentage. This relationship shows that a lower growth rate requires more years to double. The starting example, 2 percent, gives approximately \(70 \div 2 = 35\) years. If the rate is reduced to half, the estimated doubling time becomes twice as long.

For a rate of 1 percent, the calculation is \(70 \div 1 = 70\) years. Therefore option C is correct. The answer is not 17.5 years, because that would correspond to a higher rate, and it is not 35 years because the rate has changed. This is an approximation, not an exact prediction, and it assumes a constant annual rate for the estimate.

Correct answer: A. A large young population is entering reproductive ages

The birth rate is a rate relative to the population, while the total number of births also depends on how many people are in the childbearing or reproductive-age groups. A country may have a large cohort of young people entering those ages. Even if each person or family has fewer births on average, the large number of potential parents can keep the total number of births high.

This situation is often described as population momentum. A falling birth rate therefore does not necessarily produce an immediate fall in total births. A zero death rate or positive migration does not directly explain the stated birth pattern, and a declining rate is not the same as a rising rate. Therefore, option A is correct.

Correct answer: A. It hides the high demographic turnover within the population

Zero population growth describes the net result: the total population at the end of a period is nearly the same as at the beginning. It does not describe the amount of movement inside the population. If births and deaths are both very high, many people are being added and removed even though these flows nearly balance. The population may therefore be changing substantially in age, health, and social composition.

Thus option A is correct: calling it only zero growth hides high demographic turnover. Zero growth does not prove that there are no births, that migration is very high, or that the death rate is low. High births and high deaths can balance each other, while migration may be small, positive, or negative. A net total is useful, but it cannot show the separate components behind that total.

Correct answer: B. Net migration

Total population growth can be separated into natural increase and net migration. Natural increase reflects births minus deaths, while net migration reflects inflows minus outflows. When both rates are stated for the same population and period, their contributions can be added to find total growth.

Here, total growth is \(0.4\%+0.9\%=1.3\%\). Net migration contributes 0.9 percentage points, which is greater than the 0.4 percentage points contributed by natural increase. Therefore, net migration makes the larger contribution, so option B is correct. This does not mean natural increase contributes nothing.

Correct answer: B. 1 percent

Total population change has two parts: natural change and net migration. Natural change is births minus deaths, while net migration is immigrants minus emigrants. After finding the total numerical change, divide it by the original population and multiply by 100 to obtain the percentage growth rate.

Natural increase is \(300000-100000=200000\). Net migration is \(50000-150000=-100000\), because emigration is larger. Total change is therefore \(200000-100000=100000\). Relative to 10,000,000, the rate is \(100000\div10000000\times100=1\) percent. Thus option B is correct.

Correct answer: A. Total growth and age structure can change in different directions

Total population and working-age population are different measures. Total population includes people of all ages, while working-age population is only one age group. These measures can move in opposite directions. For example, the total may rise because older people live longer or because children and elderly migrants enter, while working-age adults leave or become a smaller share of the population.

Thus, option A is correct: total growth and age structure can change in different directions. The information does not prove that birth rates are rising, that migration is zero, or that growth is impossible. An ageing population, selective out-migration of workers, or different age-specific flows could produce the stated pattern. The conclusion is possible, not the only explanation.

Correct answer: B. Negative net migration

Correct answer: B, negative net migration. Natural increase is calculated as the birth rate minus the death rate: 20 − 6 = 14 per thousand, which equals 1.4 percent. But the reported total growth is only 0.8 percent, which is 0.6 percentage points lower. Therefore, people leaving the country must be reducing the population growth; net migration is negative, approximately −0.6 percent or −6 per thousand. A is wrong because positive migration would add to 1.4 percent and make total growth higher. C contradicts the stated death rate and would make natural increase zero, not explain the given figures. D is wrong because births clearly contribute to natural increase. Memory cue: total growth = natural increase + net migration.

Correct answer: C. 6 per thousand

Population change has two parts: natural increase, which is births minus deaths, and net migration. Birth and death rates are given per thousand, so the total growth rate of 0.4 percent must first be converted to per thousand: 0.4 percent equals 4 per thousand.

Natural increase is \(11 - 13 = -2\) per thousand, meaning deaths exceed births by 2 per thousand. The relation is total growth = natural increase + net migration. Hence \(4 = -2 +\) net migration, so net migration is 6 per thousand. Therefore, option C is correct; positive migration offsets the natural decrease.

Correct answer: B. Growth may persist longer in the younger country because of population momentum

Current growth rate and future growth are not determined by the rate alone. Age structure matters because a young population contains many people who will enter reproductive ages in the future. Even if fertility declines, the large number of potential parents can keep the number of births relatively high for some time. This continuing effect is called population momentum.

Therefore, option B is the most appropriate. The younger country may sustain growth longer than the older country, even though both currently grow at 1.5 percent. An older population generally has fewer people entering reproductive ages and may face slower growth or decline, though the exact future also depends on fertility, mortality, and migration. Options A, C, and D make absolute claims that the information does not support.

Correct answer: B. Negative 800000

Total population change is made up of natural increase plus net migration. Natural increase reflects births minus deaths, while net migration reflects people entering minus people leaving. Therefore, if total change and natural increase are known, net migration is found by subtracting natural increase from total change.

Using the values, \(400000=1200000+\text{net migration}\). Hence, net migration is \(400000-1200000=-800000\). The negative sign means that 800000 more people left than entered. In Indian notation, this is a net out-migration of 8 lakh. Therefore, option B is correct. Population size itself is not needed for this calculation.

Correct answer: B. 60.5 million

A repeated annual percentage increase is applied to the new population each year, so it is compound growth rather than simple addition. After one year, multiply by \(1.10\). After two years, multiply by \(1.10\) again. This method ensures that the second increase is calculated on the already increased population.

Starting with 50 million, after one year the population is \(50\times1.10=55\) million. After the second year it is \(55\times1.10=60.5\) million, or 6.05 crore. Equivalently, \(50\times1.10^2=60.5\) million. Therefore, option B is correct. Simply adding 20 percent to the original gives 60 million and ignores compounding.

Correct answer: B. No, because the second decline applies to the smaller new population

Correct answer: B. Successive percentage changes are applied to the changing population, not always to the original population. Suppose the initial population is 100. After a 10 percent decline, 90 remain. In the second year, 10 percent of 90 is 9, leaving 81. The final population is therefore 81, so the total decline is 19 out of 100, or 19 percent—not 20 percent. A is wrong because it adds the rates without considering the new base. C is wrong because zero migration does not make successive percentage declines additive; the calculation still uses the reduced population. D is wrong because populations can decline when deaths, out-migration, or other losses exceed additions. Memory cue: apply each percentage to the current value. Two successive 10 percent decreases leave 0.9 × 0.9 = 0.81, or 81 percent of the original.

Correct answer: A. Because absolute increase also depends on population size

A percentage growth rate describes proportional change, not the exact number of people added. When a rate falls from 3 percent to 1 percent, the rate itself becomes one-third of its former value. However, the absolute increase is calculated by applying the rate to the population base, so the base population must also be known.

For example, 3 percent of 1 million is 30,000, while 1 percent of 2 million is 20,000. The latter is not necessarily one-third of the former because the population bases differ. Even with the same base, the added number would be one-third in a single comparable period, but changing population size and time context can alter the comparison. Thus option A is the sound caution.

Correct answer: A. Natural decrease is larger than positive migration

Total population change is the combined result of natural change and net migration. Positive net migration adds people to a country. If the total population nevertheless falls, another component must be negative enough to outweigh that gain. In this situation, the natural component must be a decrease, meaning deaths exceed births, and its size must be greater than the migration gain.

Therefore, natural decrease is larger than positive migration, so option A is correct. Positive migration does not prove that births exceed deaths; it only means more people entered than left. Since the total still declined, the negative natural change was stronger than the positive migration. The statement does not allow us to calculate exact numbers, but it does establish this comparison.

Correct answer: A. Natural increase is larger than negative migration

Total population change has two main components: natural increase and net migration. In simple form, \(\text{total growth}=\text{natural increase}+\text{net migration}\). Negative net migration means more people leave than enter, which lowers the population. If the total population still rises, the positive contribution from births minus deaths must be larger than that migration loss.

Thus option A is the logical conclusion: natural increase is larger than negative migration in absolute effect. For example, a natural increase of 2 percent combined with net migration of -1 percent gives total growth of 1 percent. Natural increase cannot be assumed to be zero, and deaths need not exceed births. Emigration is reducing, not increasing, total growth in this situation.

Correct answer: B. 300,000

Correct answer: B, 300,000 people, or 3 lakh. First find the total growth rate by combining natural increase and net migration: 1.4 percent + (−0.4 percent) = 1.0 percent. Now calculate 1 percent of 30 million: 30,000,000 × 0.01 = 300,000. Thus, the population increases by approximately 3 lakh in one year. A is too small and does not equal 1 percent of 30 million. C, 420,000, is the natural increase alone: 1.4 percent of 30 million, so it ignores the population loss through migration. D is too large and applies an incorrect rate. The negative migration rate reduces, but does not completely cancel, the positive natural increase. Memory cue: combine signed rates first, then multiply the resulting rate by the population.

Correct answer: A. Negative 4 per thousand

Total growth equals natural increase plus net migration. First calculate natural increase from the birth and death rates. Then express the given total growth in the same unit, subtract natural increase from total growth, and interpret the sign of the result. A negative answer indicates net out-migration.

Natural increase is \(15-5=10\) per thousand, or 1.0 percent. Total growth of 0.6 percent equals 6 per thousand. Therefore, net migration is \(6-10=-4\) per thousand. The country’s natural increase is partly cancelled by more people leaving than entering. Hence option A, negative 4 per thousand, is correct.

Correct answer: A. Population ageing

Fertility measures the level of childbearing, while life expectancy describes how long people tend to live. Declining fertility means that younger generations may be smaller. Rising life expectancy allows more people to survive into older ages. When these two trends occur together, older age groups form a larger share of the total population, even if total population growth is slowing.

Therefore option A, population ageing, is the most likely long-term change. A faster population explosion is inconsistent with declining fertility and slowing growth. The proportion of young people will not necessarily keep rising, and rising life expectancy does not imply a sharp increase in mortality. The age structure can change substantially even while the total number of people remains stable or grows slowly.

Correct answer: A. Total population size is declining

Birth rate is a relative measure: it compares the number of births with the size of the population, usually per thousand people. The total number of births, however, depends on both the rate and the total population size. If the rate remains stable but the population becomes smaller, the same proportion applied to a smaller base will produce fewer births in absolute numbers.

For example, a stable rate applied to 10 million people can produce more births than the same rate applied to 8 million people. Therefore option A is a possible explanation. A rising birth rate contradicts the condition, and stopping deaths or having positive net migration does not necessarily explain fewer births. The supplied answer is correct, though population age structure could also influence actual births.

Correct answer: B. Negative 0.8 percent

Total population growth is the sum of natural increase and net migration. If the total population is stable, total growth is zero. A natural increase of 0.8 percent means births exceed deaths by that amount, so migration must produce an equal decrease to keep the overall population unchanged.

Set up the relation \(0.8+\text{net migration}=0\). Solving gives net migration \(=-0.8\) percent. The negative sign means net out-migration: more people leave than enter. A positive 0.8 percent would add to natural growth and make the population rise, while zero migration would leave the natural increase uncancelled. Therefore, option B is correct.

Correct answer: B. 0.6 percent

Total population growth is the combined result of natural increase and net migration. Therefore, the relationship is total growth rate = natural increase rate + net migration rate. To find the migration rate, rearrange this relationship by subtracting the natural increase from the total growth. Both rates are percentages, so they can be subtracted directly.

Net migration rate = 1.5 − 0.9 = 0.6 percent. Therefore, option B is correct. The positive sign means that immigration exceeded emigration by an amount equal to 0.6 percent of the relevant population. If migration had been zero, total growth would have remained 0.9 percent. The value 0.4 percent would leave the total at 1.3 percent, not the stated 1.5 percent.