Answer:
-18.18%
Explanation:
The percentage change is the ratio of the change in price divided by the initial price, it can be calculated by the formula below:
Percentage change = [tex]\frac{(Pn - Po)}{Po} * 100%[/tex]
Where Pn = New price
Po = Initial or old price
Pn = $18
Po = $22
Percentage change = {($18 - $22)/$22} * 100%
= {($18 - $22)/$22} * 100%
= {-$4/$22} * 100%
= -0.1818181818 * 100%
= -18.18181818%
= -18.18% (to two decimal places).
The negative figure means they are complementary goods, that is goods that are consumed together.