Answer = D. $100 trillion
Solution =
Country's debt-to-GDP ratio if currently 50% = [tex]\frac{1}{2}[/tex]
⇒ [tex]\frac{Debt}{GDP} = \frac{1}{2}[/tex]
⇒ GDP = 2(Debt)
So right now ,when debt is 40 trillion, GDP will be 2×40 = 80 trillion
After 5 years when debt is 80 trillion, GDP will be 2×50 = 100 trillion