Answer:
Your expected gain is of $10.7.
Explanation:
Expected earnings:
The expected earnings is each prize multiplied by it's probability of being earned.
So
5% probability of earning $25.
5*15% = 75% probability of earning $15.
20% probability of earning $1. So
0.05*25 + 0.75*15 + 0.2*1 = 12.7
Cost of token:
The token costs $2, which means that we subtract $2 from the expected earnings.
12.7 - 2 = 10.7
Your expected gain is of $10.7.