Using the midpoint formula, calculate elasticity for each of the following changes in demand. P1 P2 Q1 Q2 Demand for: a. Cashews $7.50 per $6.00 per 800 pounds 1,000 pound pound per month pounds per month b. Portable $80 $120 75 per year 65 per year hard drive (4 terabytes) c. 6-gauge $0.60 per $0.45 per 2,500 lineal 5,000 lineal copper wire lineal foot lineal foot feet per week feet per week d. Toothpaste $2.00 per $2.40 per 10 tubes 9 tubes tube tube per month per month