When price of a food rises from Rs.20 per unit to Rs.23 per unit, its demand falls 30%. Calculate price elasticity of demand

Dear student,
E_d = (-) $\frac{Percentage change in quantity demanded}{Percentage change in price}$

Percentage change in price =$\frac{Change in price}{Original price}$ * 100
                                            = $\frac{(New price -original price)}{original price}\times 100$
                                           = $\frac{(23-20)}{20}\times 100 = 15\%$

E_d = (-) $\frac{Percentage change in quantity demanded}{Percentage change in price}$ = $(-)\frac{30}{15} = (-) 2$

Regards.