(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)
(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)
(3,1) (3,2) (3,3) (3,4) (3,5) (3,6)
(4,1) (4,2) (4,3) (4,4) (4,5) (4,6)
(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)
(6,1) (6,2) (6,3) (6,4) (6,5) (6,6)
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P(1 or 2) = P(green roll) = 3 ways out of 36 = =
P(10) = P(red roll) = 3 ways out of 36 = =
P(any other roll) = P(purple roll) = 31 ways out of 36 = =
Roll Probability Winning (+) Expectation
or loss (-)
(X) P(X) W(X) P(X)*W(X)
----------------------------------------------
green 1/12 +$12 $1
red 1/12 -$9 -$3/4
purple 5/6 $w $5/6w
----------------------------------------------
Total expectation = $1/4 + 5/6w
For the game to be fair, the total expectation must be 0.
1/4 + 5/6w = 0
5/6w = -1/4
Multiply both sides by 12
10w = -3
w = -3/10 = -$.30
You should lose 30 cents if you get a purple roll.
Edwin
Question 871692
(1,1) (1,2) (1,3) (1,4) (1,5) (1,6)
(2,1) (2,2) (2,3) (2,4) (2,5) (2,6)
(3,1) (3,2) (3,3) (3,4) (3,5) (3,6)
(4,1) (4,2) (4,3) (4,4) (4,5) (4,6)
(5,1) (5,2) (5,3) (5,4) (5,5) (5,6)
(6,1) (6,2) (6,3) (6,4) (6,5) (6,6)
<
P(1 or 2) = P(green roll) = 3 ways out of 36 = =
P(10) = P(red roll) = 3 ways out of 36 = =
P(any other roll) = P(purple roll) = 31 ways out of 36 = =
Roll Probability Winning (+) Expectation
or loss (-)
(X) P(X) W(X) P(X)*W(X)
----------------------------------------------
green 1/12 +$12 $1
red 1/12 -$9 -$3/4
purple 5/6 $w $5/6w
----------------------------------------------
Total expectation = $1/4 + 5/6w
For the game to be fair, the total expectation must be 0.
1/4 + 5/6w = 0
5/6w = -1/4
Multiply both sides by 12
10w = -3
w = -3/10 = -$.30
You should lose 30 cents if you get a purple roll.
Edwin