If the quantity demanded of pears falls by 4% when the price of apples decreases by 3%, then apples and pears are best described as:
The cross elasticity of demand is defined as the percentage change in quantity demanded divided by the percentage change in the price of a substitute or complement. If the cross elasticity of demand is positive, the goods are substitutes. In this case, the 4% decline in quantity of pears is divided by the 3% decline in the price of apples, which is a positive number: -4/-3 = +1.33.