JAMB Economics 2012 Paper

Concept:Each sector’s angle in the pie chart represents its fraction of the total GDP.Explanation:Total angle in a pie chart is $360^\circ$.Oil, agriculture, and mining sectors have angles $160^\circ$, $90^\circ$, and $30^\circ$ respectively.The sum of these angles is $160^\circ + 90^\circ + 30^\circ = 280^\circ$.So the manufacturing sector angle is $360^\circ - 280^\circ = 80^\circ$.Given GDP is $\mathrm{N}60$ billion.Oil sector contribution is $\frac{160}{360} \times 60 = 26.67$ billion.Manufacturing sector contribution is $\frac{80}{360} \times 60 = 13.33$ billion.Difference between the two contributions = $26.67 - 13.33 = 13.34$ billion.This is approximately $13.3$ billion.Answer:B. $13.3$ billion.