Sunglow, a publicity firm, uses the balance sheet approach to estimate uncollectible accounts expense. At year$-$end an aging of the accounts receivable produced the following classification:

Not yet due $$400,000$

$1-30$ days past due $150,000$

$31-60$ days past due $60,000$

$61-90$ days past due $20,000$

Over $90$ days past due $50,000$

Total $$680,000$

On the basis of past experience, the company estimated the percentages probably uncollectible for the above five age groups to be as follows: Group $1-1\%$; Group $2-4\%$; Group $3-10\%$; Group $4-25\%$; and Group $5-40\%$;

The Allowance for Doubtful Accounts before adjustments at December $31$ showed a credit balance of $$6,600.$

You are required to:

a$.$ Compute the estimated amount of uncollectible accounts based on the above classification by age groups.$(2$ points$)$

b$.$ Prepare the adjusting entry needed to bring the Allowance for Doubtful Accounts to the proper amount. $(3$ points$)$

c$.$ Assume that on January $15$ of the following year, Sunglow learned that an account receivable that had originated on September $1$ in the amount of $$2,400$ was worthless because of the bankruptcy of the client, May Flowers. Prepare the journal entry required on January $15$ to write off this account. $(3$ points$)$