Answer: -6%
Explanation:
The Cross price elasticity of demand shows the change in the quantity demanded of one good as a result of the change in price of another good.
Negative cross elasticity means that both goods are complimentary in that an increase in price in one leads to a decrease in quantity demanded in the other good. The reverse holds true
Cross price elasticity = Percent change in quantity demanded of good X / Percent change in price of good Y
-3 = Percent change in quantity demanded of good X / 2%
Percent change in quantity demanded of good X = -3 * 2%
= -6%
Quantity demanded of good X decreased by 6%.