JAMB Economics 2019 Paper

Concept:Price elasticity of demand measures how much quantity demanded changes when price changes.Explanation:Moving from price $8$ to $6$, quantity demanded moves from $10$ to $12$.Change in quantity demanded: $12 - 10 = 2$.Percentage change in quantity demanded: $\frac{2}{10} = 0.2$ or $20\%$.Change in price: $6 - 8 = -2$.Percentage change in price: $\frac{-2}{8} = -0.25$ or $-25\%$.Elasticity of demand = $\frac{\% \Delta Q}{\% \Delta P} = \frac{0.2}{-0.25} = -0.8$.Ignoring the negative sign, elasticity is $0.8$.Answer:C. 0.8