If a $1 increase in price leads to a 3-unit decrease in quantity demanded, then demand must be elastic

According to the quantity theory of money, if the quantity of goods and services doubles within the economy while velocity is constant and the money supply is cut in half, then the price level will be

a. unaffected b. four times higher c. times higher d. one-half its previous level e. one-fourth its previous level

The most basic investigative tool of economics is the

a. concept of scarcity. b. mechanism of supply and demand. c. coordination and trade syndrome. d. inflation-unemployment trade-off. e. regulation of business.