This is a pie-chart showing the age distribution of population. The total population is 120 million. The official school-leaving age is 18 years while the o...

Reading the chart. The three sectors of a pie chart must total \(360^\circ\). The \(18\text{-}54\) sector carries a right-angle mark, so it is \(90^\circ\), and the \(55+\) sector is \(108^\circ\). The remaining \(0\text{-}17\) sector is therefore \(360^\circ - 90^\circ - 108^\circ = 162^\circ\). (The figure printed near it, \(182^\circ\), cannot be right because \(182+90+108 = 380^\circ\), which is more than a full circle.)

Each group \(= \dfrac{\text{sector angle}}{360^\circ}\times 120\text{ million}.\)

(a)(i) Children, 0-17 years

\[\dfrac{162}{360}\times 120 = 54\text{ million}\]

(a)(ii) Old people, 55+ years

\[\dfrac{108}{360}\times 120 = 36\text{ million}\]

(a)(iii) Working population, 18-54 years

\[\dfrac{90}{360}\times 120 = 30\text{ million}\]

Check: \(54 + 36 + 30 = 120\) million.

(b) Economic implication

Only 30 million people, a quarter of the nation, are of working age, yet they must support 90 million dependants (54 million children and 36 million elderly). The dependency ratio is \(\dfrac{90}{30} = 3:1\), which is extremely high. The consequences are:

• A very heavy dependency burden on each worker, so the average standard of living is low.
• High consumption but low savings and investment, which slows capital formation and growth.
• Large public spending on education for the many children and on pensions and health care for the aged.
• A small effective labour force relative to the whole population, which limits total national output.