Question

A bag contains 7 green marbles, 3 yellow marbles and 10 black marbles. If a green marble is drawn, you win $20. If a yellow marble is drawn, you win $30. If a black marble is drawn, you lose $15. It costs $1 to play. What are you expected winnings over time?

Answer 1

Explanation:

chances of winning $20=7/20

chances of winning $30=3/20

chances of winning $15=1/2