30. An increase in the number of fast-food restaurants: Select one: O a. increases the demand for substitutes for fast-food meals. O b. increases the demand for fast-food meals. O c. raises the price of fast-food meals. O d. increases the supply of fast-food meals. 6. A 10 percent increase in the quantity of spinach demanded results from a 20 percent decline in its price. The price elasticity of demand for spinach is: Select one -0.5 O b.0.5 200 d. 10.0