The monthly salary of a policeman is 25 ♌ as time goes price increase to $35 so he could now able to afford 40 loaves of bread instead of 20 . Find you the value of elasticity demand

Change in quantity ($\Delta Q$) = $Q_2 - Q_1 = 40 - 20 = 20$ loaves
Average quantity ($Q_{avg}$) = $\frac{Q_1 + Q_2}{2} = \frac{20 + 40}{2} = \frac{60}{2} = 30$ loaves
Percentage change in quantity = $\frac{\Delta Q}{Q_{avg}} = \frac{20}{30} = \frac{2}{3}$

Change in income ($\Delta I$) = $I_2 - I_1 = 35 - 25 = 10$ ♌
Average income ($I_{avg}$) = $\frac{I_1 + I_2}{2} = \frac{25 + 35}{2} = \frac{60}{2} = 30$ ♌
Percentage change in income = $\frac{\Delta I}{I_{avg}} = \frac{10}{30} = \frac{1}{3}$

The value of the income elasticity of demand is 2.