Price (Rs) (P)	Total expenditure (TE) (Rs)	Ounatity demanded (TE/P) (units)
10 9	180 162	[180 / 10] 18 [162 / 9]18

\(\Delta P = 9-10 =-1, \Delta Q = 18-18=0\)
Percentage Change in Quantity Demanded
= \(\frac{\Delta Q}{Q}\times 100\)
= \(\frac{0}{18}\times100\) = 0
Percentage change in Price
= \(\frac{\Delta P}{P}\times 100=\frac{1}{100}\times 100 \)= Rs.10
\(E_d=\frac{Percentage \ \ Change \ \ in \ \ Quantity \ \ Demanded}{Percentage \ \ Change \ \ in \ \ Price}\)
\(=\frac{0}{10}=0\)
\( E_d=0\) (Perfectly inelastic demand)