Calculating Expected Value w/ Toy Game

mathnoob1234

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How do I go about calculating the expected value of this situation:

We are playing a game, and have accumulated 10 points thus far in our turn. At the end of our turn we have the option to roll a dice - if the roll is > 4 then we get to add on 20 points to our current 10, if it is <= 4 then we lose our points and end the turn at 0. One added condition is that if we end the turn with 0 points, we get penalized an additional 6 points. If we refuse the option we end the turn at 10 points.

What I currently have is:

Roll option
EV = EV(dice>4) + EV(dice<=4) = (2/6) * (10 + 20) + (4/6) * (0 - 6) = 6

No Roll option
EV = 10

Is this correct? Or do I need to pretend that I am losing the 10 points when I roll <= 4 to make that term -16 instead of -6? Any help in clarifying this is appreciated thanks!
 
Both ways result in a roll ev of 6, I guess they are the same? Just adding the full 10 in front vs 1/3 X 10 and 2/3 X 10?
 
How do I go about calculating the expected value of this situation:

We are playing a game, and have accumulated 10 points thus far in our turn. At the end of our turn we have the option to roll a dice - if the roll is > 4 then we get to add on 20 points to our current 10, if it is <= 4 then we lose our points and end the turn at 0. One added condition is that if we end the turn with 0 points, we get penalized an additional 6 points. If we refuse the option we end the turn at 10 points.

What I currently have is:

Roll option
EV = EV(dice>4) + EV(dice<=4) = (2/6) * (10 + 20) + (4/6) * (0 - 6) = 6

No Roll option
EV = 10

Is this correct? Or do I need to pretend that I am losing the 10 points when I roll <= 4 to make that term -16 instead of -6? Any help in clarifying this is appreciated thanks!
I agree with your calculations. You would use -16 if you were interested in the difference between the current and the final states. This is how post #2 does it, but it has the same answer because the current 10 points are added to the difference.
 
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