FIGURE 7.1 Copper: price and output, 1900-2010 (source: US Geological Survey) services in state X? To the extent that you can, and making the nec- essary assumptions as you go along, indicate the expected effects on price and quantity; the relative magnitude of these effects; and any possible differences between short-run and long-run effects. I 7.6. T-shirt printing. The custom T-shirt printing business has many competitors, so that the perfect competition model may be con- sidered a good approximation. Currently the market demand curve is given by Q = 120 - 1.5 p, whereas the market supply is given by Q = 20 + 2 p. (a) Determine the market equilibrium Suppose there is a T-shirt craze that increases demand by 10% (that is, for each price, demand is now 10% greater than it was before the price increase). (b) Determine the new demand curve. (c) Determine the change in equilibrium quantity. (d) If your answer to the previous question is different from 10%, explain the difference in values. Now go back to the initial demand curve and suppose there is an in