3.As the price of good X rises from $10 to $12, the quantity demanded of good Y rises from 100 units to 114 units. What is the cross elasticity of demand? Are X and Y substitutes or complements? Explain.

4.The quantity demanded of good X rises from 130 to 145 units as income rises from $2,000 to $2,500 a month. What is the income elasticity of demand?

5.The marginal utility of good A is 4 utils, and its price is $2, and the marginal utility of good B is 6 utils, and its price is $1. Is the individual consumer maximizing (total) utility if she spends a total of $3 by buying one unit of each good? Show the calculation and explain.