Questions about 1.28 puzzler: Manager's role what exactly can be disclosed?

My quick-and-dirty solution (which will not win any prizes): everyone agrees that, tomorrow, he/she will bring 1/7 of his/her salary in Monopoly money, and deposit it into a box. Someone then counts the contents of the box, and that is the average salary. Granted, if one’s salary is not evenly divisible by 7, then the result will be off a little (unless they use play money coins to get to within the nearest cent). (I’m sure the unwritten rules of the puzzler require that they be able to calculate the average now, rather than tomorrow.)