What are controls required in a perpetual inventory system and give example?

Colorado rocky cookie company offers credit terms to its customers. at the end of 2018, accounts receivable totaled $715,000. the allowance method is used to account for uncollectible accounts. the allowance for uncollectible accounts had a credit balance of $50,000 at the beginning of 2018 and $30,000 in receivables were written off during the year as uncollectible. also, $3,000 in cash was received in december from a customer whose account previously had been written off. the company estimates bad debts by applying a percentage of 15% to accounts receivable at the end of the year. 1. prepare journal entries to record the write-off of receivables, the collection of $3,000 for previously written off receivables, and the year-end adjusting entry for bad debt expense.2. how would accounts receivable be shown in the 2018 year-end balance sheet?