Answer:
$5
Explanation:
You need to calculate the expected value of this game.
There are 4 equally likely outcomes:
1. heads-heads
2. heads-tails
3. tails-heads
4. tails-tails
The winnings for each outcome is:
1. heads-heads $20
2. heads-tails $0
3. tails-heads $0
4. tails-tails $0
Each outcome has a 0.25 probability of occurring.
The expected value is the sum of the products of the probability of each outcome and its winnings
expected value = 0.25 * $20 + 0.25 * $0 + 0.25 * $0 + 0.25 * $0
expected value = $5
To be a fair game, each play should cost $5.