The trial balance of Marin Inc. on June 30, 2017 is as follows: Debit Credit Cash $3,560 Accounts receivable 4,006 Supplies 990 Equipment 4,710 Accounts payable $3,306 Unearned revenue 1,490 Common shares 7,440 Retained earnings 3,470 Service revenue 2,950 Salaries and wages expense 4,220 Office expense 1,170 $18,656 $18,656 The following transactions took place in July 2017: 1. Payments received from customers on account amounted to $1,640. 2. A computer