Solve this question and please no links answer fast q15

Dear student
Price and quantity demanded of product X
P₀ = Rs. 4
Q₀ = 100
P1 = $4\times 50\% = Rs. 2$
Q1     $=100 - 20 = 80$

Price Elasticity of supply of X = $$\begin{gathered} \frac{\% Change in quantity}{\% change in price}\times \frac{P0}{Q0} \\ =\frac{(100-80)}{(4-2)}\times \frac{4}{100} \\ =\frac{20}{2}\times \frac{4}{100} \\ =0.4 \end{gathered}$$
$$\begin{gathered} Price elasticity of supply of X= \frac{1}{2}Price elasticity of Y \\ Price elasticity of Y = 2 \times price elasticity of X \\ Price elasticity of Y = 2\times 0.4 = 0.8 \end{gathered}$$

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