This homework question is confusing me, can you show me how to solve it?

For her Games Fair project, Lucia created a spinner with 15 sections with numbers 1 to 15 on each section. She charges each player $1 to play this game. The rule is simple. If a multiple of 3 (i.e. 3, 6 ...) is rolled the player wins $3. If a multiple of 7 is rolled the player wins $5.

Is this a profitable game?

To whom is it profitable?

How do you know?

Support your answer with mathematical reasoning and provide a clear explanation.