please explain step by step as to how you got the answers for these problems

21. During 2019, Purple Inc. had sales on account of $198,000, cash sales of $81,000, and collections on account of $126,000. In addition, they collected $2,175 which had been written off as uncollectible in 2017. As a result of these transactions, the change in the accounts receivable balance indicates a a. $69,825 increase. b. $72,000 increase. c. $150,825 increase. d. $153,000 increase. 23. Blue Company uses the percentage of sales method for recording bad debt expense. For the year, cash sales are $1,000,000 and credit sales are $1,500,000. Management estimates that 2% is the sales percentage to use. What adjusting entry will Blue Company make to record the bad debt expense? a. Bad Debt Expense 30,000 Allowance for Doubtful Accounts 30,000 b. Bad Debt Expense 50,000 Allowance for Doubtful Accounts 50,000 c. Bad Debt Expense 30,000 Accounts Receivable 30,000 d. Bad Debt Expense 50,000 Accounts Receivable 50,000