Answer:
Value of Stockholder's equity at year end = $40,000
Explanation:
As with every transaction the standard statement
"Assets = Equity + Liability" remains constant.
As when the business was started,
Assets = $50,000, Liabilities = $30,000
Thus, Equity = $50,000 - $30,000 = $20,000
During the year net revenue earned = $90,000 - $60,000 - $10,000 = $20,000
This net revenue will increase equity at the end of year.
As Opening equity + increase in current year = $20,000 + $20,000 = $40,000 = Value of Equity at Year end.