Suppose that a firm makes two products, a and b. the sales mix in units for the period is 70% for a and 30 % for b. if the unit contribution margin for a is $8.75 and the unit contribution margin for b is $5.31, then the weighted-average unit contribution margin is: (input your answer using two decimal places. do not use commas or dollar signs. don't round any intermediate calculations).

Alaska king crab fishing in the 1960s and '70s was a dangerous but rich fishery. boats from as far away as california and japan braved the treacherous gulf of alaska crossing to reach the abundant king crab beds in cook inlet and bristol bay. suddenly, in the early 1980s, the fishery crashed due to over fishing. all crabbing in those areas ended. to this day, there is no crabbing in bristol bay or cook inlet. a. how would an economist explain the decline of the alaska king crab fishery