Population Growth

Correct answer: B. 10 percent

Percentage population growth compares the increase with the starting population, not with the final population. The population rises from 40 million to 44 million, so the absolute increase is 4 million. Dividing this increase by the initial 40 million and multiplying by 100 gives 10 percent. Therefore, the correct choice is B.

Use \(\text{percentage growth}=\frac{\text{increase}}{\text{initial population}}\times100\). The calculation is \(\frac{44-40}{40}\times100=\frac{4}{40}\times100=10\%\). In crore units, the same calculation is \(\frac{0.4}{4}\times100=10\%\). Choice A understates the increase, while 40 percent incorrectly treats the original population as the increase.

Correct answer: C. Increase of 400000

Total population change has two parts: natural increase and net migration. Natural increase is births minus deaths. Net migration is immigrants minus emigrants. Both parts must be included; counting births alone or ignoring migration would give an incorrect result.

Natural increase = \(900000 - 600000 = 300000\). Net migration = \(200000 - 100000 = 100000\). Therefore, total change = \(300000 + 100000 = 400000\). The population increases by 400,000, or 4 lakh, so option C is correct. The 3-lakh answer includes only natural increase and misses the additional 1 lakh gained through migration.

Correct answer: A. 1.8 percent

The correct answer is A: 1.8 percent. Natural increase means births minus deaths, so 26 − 8 = 18 per thousand. A per-thousand value must be divided by 10 to convert it into a percentage because 1,000 = 100 × 10; therefore, 18 per thousand = 1.8 percent. Option A is correct because it gives both the right subtraction and the right unit conversion. Option B, 18 percent, forgets to convert per thousand into percent. Option C, 0.18 percent, divides by 100 instead of 10 and is ten times too small. Option D, 2.6 percent, uses the birth rate alone rather than subtracting deaths. Memory cue: first subtract births and deaths, then change “per thousand” to percent by dividing by 10.

Correct answer: D. Decrease of 200000

The correct answer is D: a decrease of 200,000, or 2 lakh. Total population change combines natural increase and net migration. Write the values with their signs: 500,000 + (−700,000) = −200,000. The negative sign means that the population falls by 200,000. Option A has the correct magnitude but the wrong direction; the larger outflow of migrants makes the result negative. Option B incorrectly adds 500,000 and 700,000 as if both were increases. Option C treats only migration as the total change and ignores natural increase. Option D includes both components and gives the correct decrease. Memory cue: total change = natural increase + net migration; a negative net-migration value is subtracted.

Correct answer: C. Country X because the same increase is a larger share of its initial population

Growth rate measures increase relative to the starting population, not merely the number added. The same absolute increase can represent very different percentages when the initial populations differ. Country X starts with 20 million and gains 2 million, while Country Y starts with 100 million and gains the same 2 million.

For X, the rate is \(2\div20\times100=10\) percent. For Y, it is \(2\div100\times100=2\) percent. Therefore, Country X has the higher growth rate, so option C is correct. Country Y has the larger absolute population, but that fact alone does not give it the larger proportional growth.

Correct answer: A. Population is still increasing but more slowly

A positive population growth rate means that the total population is still increasing. If the rate is steadily declining, the population is growing more slowly than before, but it has not necessarily started to fall. A negative rate would be needed to show a decrease, unless other information changed the interpretation. Therefore, choice A is the most accurate conclusion.

For example, a population growing at 2 percent is increasing faster than one growing at 1 percent, but both rates still produce an increase. A falling rate describes the changing speed of growth, not automatically a fall in population. The information does not prove that natural increase is zero or that migration is negative. Thus choices B, C, and D make claims that cannot be established from the given statement.

Correct answer: B. Increase of 300000

The correct answer is B: an increase of 300,000, or 3 lakh. Natural increase is births minus deaths. Since births equal deaths, natural increase is 0. Immigration minus emigration is net migration, and immigration exceeds emigration by 300,000, so net migration is +300,000. Total population change = 0 + 300,000 = +300,000. Option A reverses the direction and would apply to net out-migration. Option B correctly identifies the positive migration balance. Option C ignores the migration effect and is therefore wrong. Option D counts the same migration difference twice. Memory cue: equal births and deaths cancel; the remaining population change comes entirely from net migration.

Correct answer: D. Zero

Total population growth includes both natural increase and net migration. Births exceeding deaths by 200,000 give a natural increase of +200,000. Net out-migration of 200,000 means more people leave than enter, so its contribution is −200,000.

Add the two components: +200,000 + (−200,000) = 0. The natural increase is exactly cancelled by the migration loss, so the total population shows no net change. Therefore option D, zero, is correct. It would be wrong to count the out-migration as an additional increase; leaving the country reduces population and must be represented with a negative sign.

Correct answer: C. Natural increase uses births and deaths while actual growth also includes migration

Natural increase measures the difference between births and deaths. It does not include people entering or leaving through migration. Actual population growth, often called total or real change, includes this natural balance as well as net migration, which is immigration minus emigration.

In symbolic form, natural increase is births minus deaths, while actual growth is births minus deaths plus net migration. A region may have positive natural increase but still lose population if many more people leave than enter. Conversely, migration can make actual growth positive even when births and deaths are nearly equal or natural increase is low. Therefore option C is correct. Options A, B, and D confuse the two measures or incorrectly claim they are always identical.

Correct answer: A. 8 per thousand

Natural increase is found by subtracting the death rate from the birth rate. Here it is \(18-7=11\) per thousand. Net migration is negative 3 per thousand, which means more people leave the country than enter it. This loss must be subtracted from the natural increase rather than added as a positive contribution.

Therefore, total growth is \(11+(-3)=8\) per thousand, or equivalently \(11-3=8\) per thousand. Option A is correct. The value 11 per thousand represents only natural increase and ignores migration. A negative migration rate does not mean that migration is zero; it reduces the total growth produced by births and deaths.

Correct answer: C. 8 per thousand

Population growth from natural causes is found by subtracting the death rate from the birth rate. Net migration must then be added, because positive net migration means more people enter the country than leave it. All the given rates use the same unit, per thousand, so they can be combined directly without another conversion.

Natural increase is \(12-9=3\) per thousand. Adding net migration gives \(3+5=8\) per thousand. The total growth rate is therefore 8 per thousand, which represents the combined effect of births, deaths, immigration, and emigration. Option C is correct. Choosing 3 would ignore the positive contribution of migration.

Correct answer: A. Natural increase may rise rapidly

Natural increase is determined by the difference between the birth rate and the death rate. If many births continue while deaths fall quickly because of better health, the gap between births and deaths becomes larger. That produces faster natural population growth in the short term. This conclusion concerns natural increase; total population growth can also be affected by immigration and emigration.

Therefore option A is correct: natural increase may rise rapidly. The word “may” allows for other influences, but the demographic effect described clearly pushes the rate upward. The population will not immediately decline, and migration does not automatically become zero. A falling death rate also does not force the birth rate to equal it. Those choices confuse separate demographic processes.

Correct answer: A. Population growth will slow

Natural population growth is the difference between the birth rate and the death rate. When the death rate is already low, reducing the birth rate makes this difference smaller. Education, urbanisation, and family planning commonly support decisions that lead to fewer births, so the natural increase slows.

Thus option A, population growth will slow, is the best answer. The total population may still rise for some time if births remain higher than deaths, but it will rise more slowly. A fall in birth rate does not immediately make deaths increase, reduce density to zero, or stop migration. Those choices do not follow from the information given.

Correct answer: B. Population momentum

Population momentum is the continued growth that can occur because a large young population is moving into reproductive ages. It reflects the age structure created by earlier high fertility. Even if fertility, meaning births per woman, falls, the number of women and couples able to have children may remain large.

Consequently, total births can stay above deaths for several decades, depending on mortality and migration. This is why option B is correct. Very high mortality and low life expectancy would generally reduce growth, while negative migration would offset it; neither explains the stated pattern as directly as population momentum.

Correct answer: A. Positive net migration is offsetting the natural decrease

Natural increase is the difference between births and deaths, excluding migration. Negative natural increase means deaths are greater than births, so the population would fall if no migration occurred. Total population, however, also changes through net migration. Positive net migration means more people enter than leave and can compensate for the natural decrease.

For example, if natural change reduces the population by 10,000 but net migration adds 10,000, the total population remains stable. Therefore option A is the most likely explanation. A high birth rate compared with deaths would produce positive natural increase, while no migration would not offset the decline. Zero population density is also impossible for a populated country.

Correct answer: C. 2 percent

The correct answer is C: 2 percent. Annual growth rate = (annual increase ÷ initial population) × 100. Both quantities are in millions, so calculate (2.4 ÷ 120) × 100 = 0.02 × 100 = 2 percent. Option A, 0.2 percent, is ten times too small and usually results from a decimal-place error. Option B, 1 percent, does not match the given ratio. Option C correctly compares the increase with the starting population. Option D, 20 percent, is ten times too large and confuses 2.4 million with a much larger share of 120 million. The 2.4 million is the absolute increase, while 2 percent is the relative rate. Memory cue: rate = increase ÷ initial population × 100.

Correct answer: B. 35 years

The Rule of 70 gives a quick estimate of the time needed for a quantity to double under a constant percentage growth rate. It is especially useful for population, money, or other quantities that grow by compounding. The rule uses the number 70 divided by the annual growth rate expressed as a percentage, not as a decimal.

Here the annual growth rate is 2 percent, so \(\text{doubling time}\approx70\div2=35\) years. This is an approximation, not an exact prediction, because real populations may have changing birth rates, death rates, or migration. Nevertheless, according to the stated rule, the correct answer is option B, 35 years.

Correct answer: C. It falls from about 70 to 35 years

The Rule of 70 gives an approximate doubling time by dividing 70 by the annual growth rate expressed as a percentage. It assumes that the growth rate remains constant throughout the period. A higher growth rate therefore means fewer years are needed for the population to double.

At 1 percent, doubling time is \(70\div1=70\) years. At 2 percent, it is \(70\div2=35\) years. Consequently, the estimated time falls from about 70 to 35 years, making option C correct. The rule is an approximation, but the comparison clearly shows that doubling the rate roughly halves the doubling time.

Correct answer: B. 550000

A 10 percent increase means that one-tenth of the initial population is added to the initial population. The new total is therefore 110 percent of the starting value, or the starting value multiplied by \(1.10\). It is important not to confuse 10 percent with adding 10,000 or with doubling the population.

Ten percent of 500,000 is \(500000\times0.10=50000\). Adding this increase gives \(500000+50000=550000\), which is 5.5 lakh. Therefore, option B is correct. The value 505,000 represents only a 1 percent increase, while 600,000 represents a 20 percent increase over 500,000. The calculation uses the original population as the base.

Correct answer: A. 760000

A decline means that a percentage of the original population is removed. The original population is 800,000, and 5 percent is written as \(0.05\). First calculate the number of people lost, then subtract that number from the original population. This avoids confusing a decrease with an increase.

The decrease is \(800000\times0.05=40000\). The remaining population is \(800000-40000=760000\), which is 7.6 lakh. Equivalently, 95 percent remains, so \(800000\times0.95=760000\). The value 840,000 would be obtained by adding 5 percent and would represent growth, not decline. Therefore, option A is correct.

Correct answer: B. 1.2 percent

The correct answer is B: approximately 1.2 percent. First find natural increase: birth rate − death rate = 22 − 10 = 12 per thousand. Because there is no migration, net migration is zero, so total growth equals natural increase. Convert 12 per thousand to percent by dividing by 10: 12 ÷ 10 = 1.2 percent. Option A, 0.12 percent, is ten times too small. Option B correctly subtracts deaths, accounts for zero migration, and converts the unit. Option C repeats 12 without changing per thousand to percent. Option D uses the birth rate approximately rather than the difference between births and deaths. Memory cue: with no migration, total growth = births − deaths; then divide a per-thousand result by 10.

Correct answer: B. 1.1 percent

The correct answer is B: 1.1 percent. Total growth rate is the sum of natural increase and net migration. Since net migration is negative, calculate 1.5 + (−0.4) = 1.1 percent, or equivalently 1.5 − 0.4 = 1.1 percent. Option A gives only the magnitude of the migration rate and ignores natural increase. Option B correctly combines both rates with their signs. Option C would be correct only if migration were positive 0.4 percent, not negative. Option D adds the figures incorrectly and does not represent the stated components. The result remains positive because natural increase is larger than the migration loss. Memory cue: preserve the sign of migration before adding rates.

Correct answer: C. Positive 0.2 percent

Total population growth combines natural increase and net migration. Natural increase already reflects births minus deaths. Net migration may be positive when more people enter than leave, or negative when more leave than enter. The two rates are added algebraically, so their signs must be retained.

Here the total rate is \(-0.3+0.5=+0.2\) percent. Although natural change reduces the population by 0.3 percent, net in-migration adds 0.5 percent, which is larger. The result is therefore a positive growth rate of 0.2 percent, making option C correct. Adding magnitudes without signs would incorrectly produce 0.8 percent.

Correct answer: A. It can remain positive

Natural increase depends on the difference between the birth rate and the death rate. Both rates may decline while the birth rate still remains higher than the death rate. In that situation, births still exceed deaths, so the natural increase remains positive, although it may be smaller than before.

For example, if the birth rate is 20 per thousand and the death rate is 12 per thousand, the natural increase is still positive at 8 per thousand. Migration is not needed to determine natural increase; it affects total population change separately. Therefore, option A is correct. It would be wrong to assume that falling rates automatically make the difference zero or negative.

Correct answer: A. A large young population with declining fertility

A large young population can create population momentum. Many young people may enter reproductive ages, so the total number of births can remain high even when the average number of children per woman, or fertility rate, is falling. At the same time, a decline in fertility reduces the potential for future growth, so the overall growth rate may begin to slow.

Thus, option A is correct: a large young population with declining fertility can produce high total births for some time while growth decelerates. “No births” is inconsistent with the stated situation, and very high deaths are not necessary for this pattern. Migration being zero also does not explain the combination as directly as age structure and fertility do.