Please do question no. 6 to 13 in English language..

Change in price ($\Delta P$) = Rs. $-2$
Change in quantity demanded ($\Delta Q$) = 10 units
Price elasticity of demand ($E_d$) = $-1$
Original price ($P$) = Rs. 10
We need to find the original quantity ($Q$).

$E_d = \frac{\Delta Q}{\Delta P} \times \frac{P}{Q}$
Substitute the given values:

The quantity demanded before the change in price was 50 units.

Price elasticity of demand ($E_d$) = $-0.2$
Percentage increase in price ($\% \Delta P$) = $5\%$
We need to find the percentage change in quantity demanded ($\% \Delta Q$).

$E_d = \frac{\% \Delta Q}{\% \Delta P}$
Substitute the given values:

The demand for the commodity falls by 1%.

Initial Price ($P_1$) = Rs. 10
Final Price ($P_2$) = Rs. 8
Initial Quantity ($Q_1$) = 20 units
Final Quantity ($Q_2$) = 30 units

The price elasticity of demand is $\boxed{-2.5}$.

Initial Price ($P_1$) = Rs. 5
Final Price ($P_2$) = Rs. 4
Initial Quantity ($Q_1$) = 100 units
Final Quantity ($Q_2$) = 150 units

The price elasticity of demand is $\boxed{-2.5}$.

Initial Price ($P_1$) = Rs. 10
Final Price ($P_2$) = Rs. 8
Initial Quantity ($Q_1$) = 100 units
Final Quantity ($Q_2$) = 120 units

The price elasticity of demand is $\boxed{-1}$.

Initial Price ($P_1$) = Rs. 10
Final Price ($P_2$) = Rs. 12
Initial Quantity ($Q_1$) = 100 units
Final Quantity ($Q_2$) = 80 units

The price elasticity of demand is $\boxed{-1}$.

Initial Price ($P_1$) = Rs. 10
Final Price ($P_2$) = Rs. 8
Initial Quantity ($Q_1$) = 100 units
Final Quantity ($Q_2$) = 150 units

The price elasticity of demand is $\boxed{-2.5}$.

Initial Price ($P_1$) = Rs. 10
Final Price ($P_2$) = Rs. 8
Initial Quantity ($Q_1$) = 100 units
Final Quantity ($Q_2$) = 120 units

The price elasticity of demand is $\boxed{-1}$.

Initial Price ($P_1$) = Rs. 10
Final Price ($P_2$) = Rs. 12
Initial Quantity ($Q_1$) = 100 units
Final Quantity ($Q_2$) = 80 units

The price elasticity of demand is $\boxed{-1}$.