Astudent in a principles of economics course makes the following remark: "the economic model of perfectly competitive markets is fine in theory but not very realistic. it predicts that in the long run, a firm in a perfectly competitive market will earn no profits. no firm in the real world would stay in business if it earned zero profits." is this remark correct or incorrect?

Upper a report about the decline of western investment in third world countries included this: "after years of daily flights comma several european airlines halted passenger service. foreign investment fell 400 percent during the 1990 s." what is wrong with this statement? choose the correct answer below. a. if foreign investment fell by 100 % comma it would be totally eliminated comma so it is not possible for it to fall by more than 100 %. b. the actual amount of the decrease in foreign investment is less than 100%. c. if foreign investment fell by 100%, it would be cut in half. thus, a decrease of 200% means that it would be totally eliminated, and a decrease of more than 200% is impossible. d. the statement does not mention the initial amount of foreign investment.