A partial adjusted trial balance of Joy Ltd at Jan 31, 2014, shows the following:

Joy Ltd.
Adjusted Trial Balance
31-Jan-14
	Debit	Credit
Supplies	600
Prepaid insurance	2,400
Salaries and wages payable		800
Unearned revenue		1,000
Service revenue		3,000
Supplies expense	950
Insurance expense	2,400
Salaries and wages expense	1,800

Required:

Answer the following questions, assuming the companys fiscal year beings January 1:

1. If the amount in Supplies Expense is the January 31 adjusting entry, and $650 of supplies was purchased in January, what was the balance in Supplies on January 1?
2. If the amount in Insurance Expense is the January 31 adjusting entry for one month of insurance expense, and the original insurance premium had been paid for one year of coverage, what was the total 12-month premium and when was the policy in effective?
3. If $2,500 of salaries and wages was paid in January, what was the balance in Salaries and Wages Payable at December 31, 2013?
4. If $1,600 was received in January for services performed in January, what was the balance in Unearned Revenue at December 31, 2013?