SOLUTION: A bag contains 3 gold marbles, 10 silver marbles, and 29 black marbles. Someone offers to play this game: You randomly select one marble from the bag. If it is gold, you win $4. If

Algebra ->  Test -> SOLUTION: A bag contains 3 gold marbles, 10 silver marbles, and 29 black marbles. Someone offers to play this game: You randomly select one marble from the bag. If it is gold, you win $4. If      Log On


   



Question 1195583: A bag contains 3 gold marbles, 10 silver marbles, and 29 black marbles. Someone offers to play this game: You randomly select one marble from the bag. If it is gold, you win $4. If it is silver, you win $2. If it is black, you lose $1.
What is your expected value if you play this game?

Answer by ikleyn(52795) About Me  (Show Source):
You can put this solution on YOUR website!
.
A bag contains 3 gold marbles, 10 silver marbles, and 29 black marbles.
Someone offers to play this game: You randomly select one marble from the bag.
If it is gold, you win $4. If it is silver, you win $2. If it is black, you lose $1.
What is your expected value if you play this game?
~~~~~~~~~~~~~~~~

The expected value of the game  E = 4*P(gold) + 2*P(silver) - 1*P(black)  dollars.


P(gold)   = 3%2F%283%2B10%2B29%29 = 3%2F42.

P(silver) = 10%2F42.

P(black)  = 29%2F42.


Therefore, the expected value of the game  E = 4%2A%283%2F42%29+%2B+2%2A%2810%2F42%29+-+1%2A%2829%2F42%29 = %284%2A3+%2B+2%2A10+-+29%29%2F42 = 3%2F42 = 1%2F14  of a dollar.


It means that you are expected to win  1%2F14  of the dollar every time (in average) as you play the game.

Solved and explained.