Guardian Security Services was established on January 15, 2014, to provide security services. The services provided during the remainder of the month are listed below. Jan. 18. Issued Invoice No. 1 to Murphy Co. for $490 on account. 20. Issued Invoice No. 2 to Qwik-Mart Co. for $340 on account. 24. Issued Invoice No. 3 to Hopkins Co. for $750 on account. 27. Issued Invoice No. 4 to Carson Co. for $680 on account. 28. Issued Invoice No. 5 to Amber Waves Co. for $120 on account. 28. Provided security services, $100, to Qwik-Mart Co. in exchange for supplies. 30. Issued Invoice No. 6 to Qwik-Mart Co. for $200 on account. 31. Issued Invoice No. 7 to Hopkins Co. for $295 on account.

Instructions
1. Journalize the transactions for January, using a single-column revenue journal and a two-column general journal. Post to the following customer accounts in the accounts receivable ledger, and insert the balance immediately after recording each entry: Amber Waves Co.; Carson Co.; Hopkins Co.; Murphy Co.; Qwik-Mart Co. 2. Post the revenue journal to the following accounts in the general ledger, inserting the account balances only after the last postings: 12 14 41 Accounts Receivable Supplies Fees Earned 3. a. What is the sum of the balances of the customer accounts in the subsidiary ledger at January 31? b. What is the balance of the accounts receivable controlling account at January 31? 4. Assume Guardian Security Services began using a computerized accounting system to record the sales transactions on February 1. What are some of the benefits of the computerized system over the manual system?