Information for Jager Company in 2021 follows:

Total net credit sales ................................................... $3,300,000
Accounts receivable at December 31 .......................... 1,250,000
Accounts receivable written off ......................................... 48,000
Amount collected on accounts previously written off
(after write off but before year end)
                                                                                                     8,000

Instructions
a. Assume that Jager Company decides to use the allowance method and estimates its uncollectible accounts to be $52,000 based on an aging schedule. What amount of bad debt expense will Jager record if Allowance for Doubtful Accounts had an opening credit balance of $30,000 on January 1, 2021?

b. Assume the same facts as in part (a), except that the Allowance for Doubtful Accounts had a $42,250 credit balance on January 1, 2021. What amount of bad debt expense will Jager record on December 31, 2021?

c. Assume instead that Jager Company decides to estimate its uncollectible accounts using 1.5% of net credit sales. What amount of bad debt expense will Jager record if Allowance for Doubtful Accounts had an opening credit balance of $30,000 on January 1, 2021?

d. How does the amount of accounts written off during the period affect the amount of bad debt expense recorded at the end of the period when using the percentage of receivables approach?

e. How does the collection of an account that had previously been written off affect the carrying amount of accounts receivable?

Why can a company not be certain what accounts are not collectible?