3. Given the following data, calculate the price elasticity of demand:

\begin{tabular}{|l|c|c|c|c|c|c|}
\hline
Price per unit & 6 & 5 & 4 & 3 & 2 & 1 \\
\hline
Quantity & 750 & 1250 & 2000 & 3250 & 4650 & 6250 \\
\hline
\end{tabular}

(a) When the price increases from 3.00 ETB per unit to 4.00 ETB per unit.

(b) When the price falls from 4.00 ETB per unit to 3.00 ETB per unit.



Answer :

Certainly! Let's proceed with the detailed, step-by-step solution for each part of the question:

### Part (a): Price increases from 3.00 ETB per unit to 4.00 ETB per unit

Given Data:
- Initial price ([tex]\(P_{initial}\)[/tex]) = 3.00 ETB
- New price ([tex]\(P_{new}\)[/tex]) = 4.00 ETB
- Initial quantity demanded ([tex]\(Q_{initial}\)[/tex]) = 3250 units
- New quantity demanded ([tex]\(Q_{new}\)[/tex]) = 2000 units

1. Calculate the Percentage Change in Price:

[tex]\[ \text{Percentage Change in Price} = \frac{P_{new} - P_{initial}}{P_{initial}} \times 100 \][/tex]

Substitute the given values:

[tex]\[ \text{Percentage Change in Price} = \frac{4.00 - 3.00}{3.00} \times 100 = \frac{1.00}{3.00} \times 100 = 33.3333\% \approx 33.33\% \][/tex]

2. Calculate the Percentage Change in Quantity Demanded:

[tex]\[ \text{Percentage Change in Quantity} = \frac{Q_{new} - Q_{initial}}{Q_{initial}} \times 100 \][/tex]

Substitute the given values:

[tex]\[ \text{Percentage Change in Quantity} = \frac{2000 - 3250}{3250} \times 100 = \frac{-1250}{3250} \times 100 \approx -38.4615\% \approx -38.46\% \][/tex]

3. Calculate the Price Elasticity of Demand:

[tex]\[ \text{Price Elasticity of Demand} = \frac{\text{Percentage Change in Quantity}}{\text{Percentage Change in Price}} \][/tex]

Substitute the calculated values:

[tex]\[ \text{Price Elasticity of Demand} = \frac{-38.4615}{33.3333} \approx -1.1538 \approx -1.15 \][/tex]

So, the price elasticity of demand when the price increases from 3.00 ETB per unit to 4.00 ETB per unit is approximately [tex]\(-1.15\)[/tex].

### Part (b): The price falls from 4.00 ETB per unit to 3.00 ETB per unit

Given Data:
- Initial price ([tex]\(P_{initial}\)[/tex]) = 4.00 ETB
- New price ([tex]\(P_{new}\)[/tex]) = 3.00 ETB
- Initial quantity demanded ([tex]\(Q_{initial}\)[/tex]) = 2000 units
- New quantity demanded ([tex]\(Q_{new}\)[/tex]) = 3250 units

1. Calculate the Percentage Change in Price:

[tex]\[ \text{Percentage Change in Price} = \frac{P_{new} - P_{initial}}{P_{initial}} \times 100 \][/tex]

Substitute the given values:

[tex]\[ \text{Percentage Change in Price} = \frac{3.00 - 4.00}{4.00} \times 100 = \frac{-1.00}{4.00} \times 100 = -25\% \][/tex]

2. Calculate the Percentage Change in Quantity Demanded:

[tex]\[ \text{Percentage Change in Quantity} = \frac{Q_{new} - Q_{initial}}{Q_{initial}} \times 100 \][/tex]

Substitute the given values:

[tex]\[ \text{Percentage Change in Quantity} = \frac{3250 - 2000}{2000} \times 100 = \frac{1250}{2000} \times 100 = 62.5\% \][/tex]

3. Calculate the Price Elasticity of Demand:

[tex]\[ \text{Price Elasticity of Demand} = \frac{\text{Percentage Change in Quantity}}{\text{Percentage Change in Price}} \][/tex]

Substitute the calculated values:

[tex]\[ \text{Price Elasticity of Demand} = \frac{62.5}{-25} = -2.5 \][/tex]

So, the price elasticity of demand when the price falls from 4.00 ETB per unit to 3.00 ETB per unit is [tex]\(-2.5\)[/tex].

### Summary:

- Part (a): When the price increases from 3.00 ETB to 4.00 ETB, the price elasticity of demand is [tex]\(-1.15\)[/tex].
- Part (b): When the price falls from 4.00 ETB to 3.00 ETB, the price elasticity of demand is [tex]\(-2.5\)[/tex].