If Wren Co. started with $50,000 in assets and $30,000 in liabilities, then it recorded $90,000 in revenues, $60,000 in expenses, and dividends of $10,000, what would Stockholders Equity be at the end of the year?

1. 90,000

2. 20,000

3. 40,000

4. 100,000

I know the answer is 40,000 because it corrected me after I chose 20,000 but I still wasn't able to figure out how to find stockholder's equity. Please show steps for how you got to your answer. Thank you