How to Find Balance Sheet Missing Amount

"Hi Sir, can you help me in solving this example?

I know it is very petty but I feel, there is wrong in the example.

Some inexperienced accountant prepared balance sheet for ABC company:

assets: liabilities:

cash 60000 notes payable 103000

accounts receivable 70000 accounts payable 112000

supplies 18000 salaries payable 20000

equipment 30000 total liabilities = 235000

trucks 42000 owners' equity:

building 50000 capital stock 120000

land 80000 retained earnings ???

operating expenses 100000

service revenue 70000

total assets = 350000 total owners equity = I don't know but it should be 115000

Compute retained earnings and what are operating expenses and service revenue in owners' equity?
thanks

Ahmed from Cairo 

Ahmed, I tried to solve this question in rough paper and I found mistake in figure of capital stock. It  should be 12000 instead of 120,000. One more thing, you should know the meaning of supplies. Supplies is not represent as sundry creditor but it represent as closing stock. Now, we are reading to show what are the balance sheet missing amount?

	Liabilities	Amount		Assets	Amount
	Notes Payables	103000		Cash	60000
	Account Payables	112000		Account receivables	70000
	Salary O/S	20000		Supplies	18000
	Total Outside Liabilities	------------- 235000		Equipment	30000
	Retained Earning	???		Capital Stock	12000
	Owner's Equity	???		Truck	30000
				Building	50000
				Land	80000
	Total  Liabilities	350000		Total Assets	350000

Now we know simple formula of accounting equation


Owner's Equity + Retained Earning = Total Assets - Total Outside Liabilities

= 350000 - 235000

Total Owner's Equity will = 1,15,000

One important second mistake is in the figures of service revenue and operating expenses
Correct figure should

Service expenses = 100,000

Operating expenses = 70,000

Now net profit will be = service revenue - operating expenses

= 1,00,000 - 70,000

= 30,000

Because business is of company, Retain earning will not be the part of total Owner's Equity

Net Owner's Equity = total owner's equity - retained earning

= 115000 - 30000 = 85000