Final answer:
Disposable income is the money that individuals and households have available to spend or save after paying taxes. The level of French disposable income is 235 francs.
Step-by-step explanation:
Disposable income is the money that individuals and households have available to spend or save after paying taxes. To calculate the level of French disposable income, we need to subtract taxes and government transfers from the GDP and add investment.
Disposable income = GDP - taxes - government transfers + investment
Using the given values: Disposable income = 300 francs - 50 francs - 30 francs + 15 francs = 235 francs