Age Structure

Correct answer: A. 53.8

The total dependency ratio compares dependants with the working-age population. Here, children and older persons together make up \(20+15=35\) percent, while the working-age group is 65 percent. The ratio is therefore \(35/65\times100\approx53.8\). It is expressed as about 53.8 dependants per 100 working-age persons, not simply as the 35 percent share of dependants.

Thus option A is correct. A common mistake is to choose 35.0 by reporting only the combined dependant percentage, but a dependency ratio requires division by the working-age population. Option C is the working-age share itself, not the ratio. Option D would result from a different denominator or calculation and is not supported by the given age structure. The percentages sum to 100, so the calculation is internally consistent.

Correct answer: A. 29.0

The old-age dependency ratio compares the elderly population with the working-age population. The standard calculation is \(\text{old-age dependency ratio}=\frac{\text{elderly population}}{\text{working-age population}}\times100\). Substituting the given percentages gives \(\frac{18}{62}\times100\approx29.03\). The result is expressed as about 29 elderly persons per 100 working-age persons.

Thus, option A, 29.0, is the correct approximate value. The 18.0 choice is only the elderly percentage and does not perform the comparison. The value 44.0 does not follow from the stated ratio, while 80.0 is also unrelated. The calculation assumes that the supplied age groups are the intended numerator and denominator.

Correct answer: A. 37.5

The youth dependency ratio compares the number of children aged 0–14 with the working-age population, here given as ages 15–59. The standard calculation is \(24/64\) multiplied by 100. Dividing 24 by 64 gives 0.375, and multiplying by 100 expresses this as 37.5 dependants per 100 working-age people.

Thus, option A, 37.5, is correct. The 24 percent figure is only the numerator, not the ratio after comparison with working-age people. Option C, 40.0, would require a different calculation, while 62.5 reverses the relationship by using 64 relative to 24. The result is a percentage-style ratio, not the share of children in the total population.

Correct answer: A. The country with a median age of 39 has a relatively older age structure

Median age divides a population into two halves: roughly half are younger and half are older than the median. A median age of 39 therefore indicates a relatively older population than a median age of 21. Median age is a summary measure, so it does not describe every detail of the age distribution, but it supports this general comparison. Option A is correct.

Correct answer: A. 1.5

The potential support ratio compares the working-age population with the dependent population. Using the percentages supplied, calculate it as \(60 \div 40 = 1.5\). The percentages can be treated as 60 working-age persons and 40 dependents out of every 100 people, so the ratio is 60 to 40, which simplifies to 1.5 to 1. It means there are about 1.5 working-age persons for each dependent person.

Option A is therefore correct. Option B, 0.67, is the reverse calculation: \(40 \div 60\), so it would represent dependents relative to working-age people, not the requested support ratio. Option C, 2.5, and option D, 40, do not follow from the stated values. This calculation assumes that “support ratio” is defined as working-age population divided by total dependent population, which is the convention used in the question.