Suppose the own price elasticity of demand for good X is -3, its income elasticity is -3, its advertising elasticity is 4, and the cross-price elasticity of demand between it and good Y is 2. Determine how much the consumption of this good will change in percentage if:
a. The price of good X decreases by 7 percent.
b. The price of good Y increases by 9 percent.
c. Advertising decreases by 2 percent.
d. Income increases by 5 percent.