At a price of 50 per unit, the Qty demand of a commodity is 1000 units. When its price falls by 10%, its Qty Demanded rises to 1080 units. Calculate price elasticity.

Step 1: Identify the given values and calculate the percentage change in price. Initial price ($P_1$) is 50 per unit. The price falls by $10\%$. Therefore, the percentage change in price ($\% \Delta P$) is: $\% \Delta P = -10\%$

Step 2: Identify the initial and new quantities and calculate the percentage change in quantity demanded. Initial quantity demanded ($Q_1$) is 1000 units. New quantity demanded ($Q_2$) is 1080 units. The change in quantity demanded ($\Delta Q$) is: $\Delta Q = Q_2 - Q_1 = 1080 - 1000 = 80 units$ The percentage change in quantity demanded ($\% \Delta Q$) is: $\% \Delta Q = \frac{\Delta Q}{Q_1} \times 100\% = \frac{80}{1000} \times 100\% = 0.08 \times 100\% = 8\%$

Step 3: Calculate the price elasticity of demand (PED). The formula for price elasticity of demand is: $PED = \frac{\% change in quantity demanded}{\% change in price}$ Substitute the calculated values: $PED = \frac{8\%}{-10\%} = -0.8$ The price elasticity of demand is $\boxed{-0.8}$.