A die decides how many balls to draw
You roll a fair six-sided die to get a number , then draw balls with replacement from a bag in which exactly one quarter of the balls are gold. You win $1 for each gold ball drawn. What is the expected winnings (in dollars, to three decimals)?
Show hints (2)+
- Given N draws, expected gold = N/4; then average over the die.
- Tower rule: E[W] = (1/4)·E[N], with E[N] = 3.5.
Answer
Reveal answer →Final answer
0.875
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