I am trying to figure out how to calculate the following and what it means - how the calculations are broken down, not just what the answer is but how i get to it.:

*Customer service requirements determine that receiving process errors should never exceed 2 percent on any given day. What percentage of the days is likely to exceed 2 percent error, given the current performance of receiving? Assume a total of 8,000 transactions per day, 4,000 in each module.