We shall try to find the difference between the imports and exports of Company B for various years one by one: For 1995: We have E = 0.75 I where E = amount of exports, I = amount of imports in 1995. E = 0.75I I - E = 0.75 x I = 0.25I. Thus, the difference between the imports and exports of Company B in 1995 is dependent on the amount of imports of Company B in 1995. Similarly, the difference for other years can be determined only if the amount of imports for these years is known. Since the imports or exports for various years are not know, the differences between and exports for various years cannot be determined.