Answer:
a. National income increases by $50,000 and factor payments to abroad increase by $20,000, so US GDP increases by $70,000
Step-by-step explanation:
The German firm hired an American worker and paid him $50,000. That means that American national income will increase by $50,000.
Since the company is German, that would increase factor payments ot abroad by the difference = $70,000 - $50,000 = $20,000.
Total GDP increases by the amount of $50,000 + $20,000 = $70,000