Question

how did gaston made a profit of 100 thousands francs

Answer 1

Gaston sold that villa to mrs al smith in 200 thousand franks so he made a profit of 100 thousand franks.

Hope this will help you..

Answer 2

Gaston bought a Villa from Juliette at 200 thousand francs while sold it at 300 thousand francs to Mrs. Al Smith. Thus in this way he made a profit of cool 100 thousand francs for a Villa which never belonged to him.