Suppose the cross-price elasticity of demand for pork with respect to the price of chicken is equal to +0

Suppose the cross-price elasticity of demand for pork with respect to the price of chicken is equal to +0.4. What does this tell you about the relation between pork and chicken?

Pork and chicken are substitutes. 1% surge in the price of pork will result in 0.4% growth in demand for chicken.

What will happen to consumption of pork if the price of chicken falls by 20%?

Cross-price elasticity of demand (XED) = percentage change in Quantity demanded of X / percentage change in Price of Y.

But

XED = +0.4

Percentage change in Price of Y = 20%

+0.4 = percentage change in Quantity demanded of X / -20%

Percentage change in Quantity demanded of X = 0.4*-20%

Percentage change in Quantity demanded of X = -8%

The consumption of pork will decline by 8%.