Age Structure

The correct answer is C: 22 percent. The three broad age groups together represent the whole population, or 100 percent. The working-age group is 72 percent and the elderly group is 6 percent. First add the known shares: 72 + 6 = 78 percent. The remaining share must belong to children, so child share = 100 − 78 = 22 percent. Option C is therefore correct. Option A would make the three groups total only 90 percent, leaving 10 percent unexplained. Option B would make the total 96 percent, also incomplete. Option D would make the total 106 percent, which is impossible if the groups are mutually exclusive and cover the whole population. The important idea is the whole-part relationship: when all categories together equal 100 percent, an unknown category is found by subtracting the known categories from 100. This question concerns age composition, especially the distribution among children, working-age people, and elderly people.

The governing concept is the dependency ratio, which expresses the number of dependents for every 100 people in the working-age population. To find the change, subtract the new value from the old value: 70 − 50 = 20. Thus, the number of dependents has decreased by 20 per 100 working-age people, so option A is correct. Option B reverses the direction of change. Options C and D use one of the original values incorrectly rather than calculating the difference. A lower ratio may reduce the potential support burden, although its economic effect also depends on employment, productivity and social services.

Total dependency is the sum of child dependency and elderly dependency. Both are measured per 100 working-age persons. The relationship is \(D_t=D_c+D_e\), where \(D_t\) is total dependency, \(D_c\) is child dependency, and \(D_e\) is elderly dependency. Substituting the given values gives \(50=D_c+20\). Therefore, \(D_c=50-20=30\) children per 100 working-age persons.

Thus, option C is correct. The figure 30 does not mean that children form 30 percent of the whole population; it is a ratio using the working-age population as the base. Option A would incorrectly treat elderly dependency as the child component, while 25 and 70 do not follow from the stated relationship. This calculation assumes that the total and elderly ratios use the same working-age denominator, which is the standard definition of dependency ratios.

The total dependency ratio combines child dependency and elderly dependency because both children and older people are treated as dependent groups in this measure. The question gives both figures using the same base: per 100 working-age persons. Therefore, they can be added directly: 40 child dependents plus 15 elderly dependents equals 55 total dependents per 100 working-age persons. Hence, choice C is correct.

There is no need to divide again or convert the figures, because both ratios already have the same denominator. Choice A results from subtracting one figure from the other, which has no demographic basis. Choice B leaves out elderly dependency, while D adds an unsupported extra amount. The result does not mean that 55 percent of the entire population is dependent; it means that the number of dependents is 55 for every 100 people in the working-age group. This distinction between a ratio and a population share is important.

Children and elderly people are generally treated as dependent age groups for this calculation. Their combined share is \(30\%+15\%=45\%\). The working-age share is the part left after removing both dependent groups from the total population: \(100\%-45\%=55\%\).

Hence option A, 55 percent working age and 45 percent dependent, is correct. The order matters because the question asks for working-age share first and dependent share second. Option B reverses the two values. Option C does not follow from the supplied percentages, and option D ignores the elderly group while treating the children’s share as the working-age share.

The total dependency ratio combines two parts: youth dependency and old-age dependency. Both are usually measured as the number of dependents per 100 people of working age. Therefore the relationship is \(\text{total dependency} = \text{youth dependency} + \text{old-age dependency}\). Substituting the given values gives \(\text{youth dependency} = 75 - 20 = 55\).

Option B is correct. The calculation assumes that all three ratios use the same denominator, namely the working-age population, which is the standard definition. It would be incorrect to add 75 and 20, because the old-age ratio is already included within the total. It would also be wrong to compare the ratios using different age bases. Thus the youth component is 55 dependents per 100 working-age people.

The working-age group in this question is defined as people aged 15–64 years. To find how many people belong to that group, multiply the total population by 70 percent. Since 70 percent equals 0.70, the calculation is \(80\text{ million}\times0.70=56\text{ million}\). Therefore, the correct choice is B, 56 million, or 5.6 crore.

The conversion is also straightforward: one crore equals 10 million, so 56 million equals 5.6 crore. The remaining 30 percent is not part of the stated working-age group and should not be added. Options A, C, and D represent different percentages or incorrect multiplication results. This calculation gives the number of people in the specified age range; it does not claim that every person in that range is employed.

Age structure describes how the total population is divided among age groups at a particular time. It commonly compares children, working-age adults and older people, although more detailed studies may use narrower age bands. The proportions help explain dependency, labour supply, schooling needs, health services and future population change.

Option A is correct because it defines age structure as the proportion or distribution of people in different ages. Birth rate is a process that affects age structure but is not its meaning. The number of employed people measures employment, and the total elderly population describes only one group. A proper age-structure analysis considers the whole population across several age categories.

In school-level demography, the 15–59 age group is generally classified as the working-age population. Many people in this range are physically and socially able to participate in employment, production and other economic activities. The group is therefore important when studying labour supply, dependency and the potential demographic dividend.

This classification is a broad statistical convention, not a claim that every person aged 15–59 is employed. Some may be studying, unemployed, caring for family members or unable to work. Similarly, children and older people are commonly treated as dependent groups in basic analysis. Thus option A, working-age population, is correct.