E #11 (Stretch problem) A partial adjusted trial balance of Rock Company at January 31, 2011, shows the following. ROCK COMPANY Adjusted Trial Balance 31-Jan-11 Debit Credit Supplies $850 Prepaid Insurance 2,500 Salaries Payable $800 Unearned Revenue 750 Supplies Expense 950 Insurance Expense 500 Salaries Expense 1,700 Service Revenue 2,000 Instructions Answer the following questions, assuming the year begins January 1. (a) If the amount in Supplies Expense is the January 31 adjusting entry, and $1,500 of supplies was purchased in January, what was the balance in Supplies on January 1? (b) If the amount in Insurance Expense is the January 31 adjusting entry, and the original insurance premium was for one year, what was the total premium and when was the policy purchased? (e) If $3,500 of salaries was paid in January, what was the balance in Salaries Payable at December 31, 2010? (d) If $1,650 was received in January for services performed in January, what was the balance in Unearned Revenue at December 31, 2010