You sell a prodect that costs you $1000 for $4,000. A customer can get get 90 day credit if they are judged to have a sufficiently low probability of default. Customers that do not default will continue to buy again after 90 days. their probability of default never changes. once there is a default, the customer cannot buy again. The required rate of return is 2% per 90 days. What is the break-even default probability (the probability associated with a NPV=0 to you?)