In the given diagram, at point R the flatter demand curve D₁D₁ is more elastic than the steeper curve DD. This is because at point R, price and quantity are the same for both the curves. Now, for a given change in price, i.e., \(\triangle\)P, the corresponding \(\triangle\)q for the flatter curve D₁D₁ is QQ₂ while for the steeper curve, it is QQ₁, QQ₂ is more than QQ_1.

Therefore, QQ₂ divided by PP₁ on the flatter curve D₁D₁ will be more than QQ₁ divided by PP₁ on the steeper curve DD, i.e.,\({QQ_2\over PP_1}>{QQ_1\over PP_1}.\)
Hence, elasticity of demand will be more on a flatter curve D₁D₁, than on a steeper curve DD.

Salt, medicine and school uniform have inelastic demand as they do not have many substitutes. On the other hand, a particular brand of lipstick has an elastic demand since they have many substitutes.

Percentage change in demand=\({\triangle Q\over Q}\times 100={18\over318}\times100=6\%\)
Price Elasticity of Demand (ED)\(={\%Change\ in\ quantity\ demanded \over \%Change\ in\ price}={6\% \over -5\%}\)
Price Elasticity of Demand (ED) = (-) 1.2
ED = (-) 1.2; Demand is more elastic because ED > 1.

\((-)0.8={20\%\over \% Change\ in\ Price}\)Percentage Fall in Price = 25%
Price for the goods will fall by 25%

\(PED={\triangle Q\over \triangle P}\times{P\over Q}\)
\(-1={\triangle Q\over 1}\times {9\over 18}\)
\(-2=\triangle Q\)
As New Price is increasing from 9 to 10, quantity demanded must decrease by\(\triangle\)Q. New Quantity = Initial Quantity + \(\triangle\)Q = 18 + (-2) = 16 At Price= 10, Quantity demanded = 16.

Price Elasticity of demand (ED)= \({\triangle Q\over \triangle P}\times {P\over Q}\)
\(-2={-20\over \triangle P}\times{5\over 50}=\triangle P=Rs1\)
As the quantity demanded is decreasing, price will increase. It means, New Price = Original Price (P) + Change in Price (\(\triangle\)P) = 5 + 1 = Rs 6 New Price = Rs 6

\(PED={\triangle Q\over \triangle P}\times{P\over Q}={0\over (-)1}\times {4\over25}=0\)
ED is perfectly inelastic as quantity demanded does not change at all in response to change in price. Thus, its demand curve will be vertical/parallel to y-axis.

Price Elasticity of demand (ED)=\({\triangle Q \over \triangle P}\times {P\over Q}={-100\over10}\times {30\over600}=(-)0.5\)
 ED = (-) 0.5 (Demand is inelastic as ED < 1)
Negative sign indicates the inverse relationship between price and quantity demanded.

Price Elasticity of Demand (ED) = \({\% \ change \ in \ quntity \ Demand \over \% \ Change \ in \ price}\)
\((-)0.2={\% \ change \ in \ quntity \ Demand \over \% 5}\)
Percentage fall in demand = 1%
Demand for the piece of goods will fall by 1%.