Friedman Jewelers uses the aging of accounts receivables method to compute its allowance for bad debts. For accounts that are 30-60 days old, they use a rate of 5% of receivables; accounts that are 60-90 days old, they use a rate of 10%; and 90-120 days old, a rate of 15%. If a customer pays at least two-thirds of the required monthly payment on a delinquent account, that partial, or "curing," payment is sufficient to treat as current the entire account and move it back into the current bucket (on which no allowance is taken). If the customer then fails again to make a required monthly payment,' the account begins the aging process again. Friedman's is supposed to write off in full any credit accounts on which no payments have been received for 120 days 1. Suppose Friedman