Answer:
The demand for candy bars is inelastic
Explanation:
The midpoint rule calculate the price elasticity of demand as percentage change in quantity divided by the percentage change in price:
% change in quantity
[tex] \frac{Q_2-Q_1}{ \frac{Q_2 + Q_1}{2} } \times 100[/tex]
The quantity demanded increased from 500 to 600. We have
[tex]Q_1 = 500 \: and \: Q_2 = 600[/tex]
[tex] \implies \frac{600 - 500}{ \frac{600 + 500}{2} } \times 100 \\ = \frac{100}{ \frac{1100}{2} } \\ = \frac{100}{550} \\ = \frac{2}{11} [/tex]
% change in price
[tex] \frac{P_2-P_1}{ \frac{P_2 + P_1}{2} } \times 100[/tex]
The price changed from 1 dollar to 0.8 dollars.
[tex] \frac{0.8 - 1}{ \frac{0.8 + 1}{2} } = - \frac{2}{9} [/tex]
Price elasticity if demand is
[tex] \frac{ \frac{2}{11} \%}{ - \frac{2}{9} \%} = - \frac{9}{11} = - 0.82[/tex]
The negative sign tells us that there is an inverse relationship between price and quantity demanded.
Since 0.82 is less than 1, the demand for candy bars is inelastic