Goofy answer when trying to solve the prisoner's dilemma (probability stuff)

[morrowcosom]

Homework Statement

Trying to find optimal solution for row player. Deny=D Tattle=T. I am trying to do this without knocking out dominated alternatives.

D T
D -1,1 -10,0

T 0,-10 -6,-6

Homework Equations

The Attempt at a Solution

DD=p(-1)+(1-p)(-10) =-1p-10+10p =9p-10
DT=p(0)+(1-p)(-6) =-6+6p

9p-10=-6+6p
3p=4
p=4/3 (Huh?)

I do not know if my arithmetic is off, or I cannot solve the game by setting both equations equal because of the (0,-10) and (-10,0) scenarios.

Thanks for the help.

Homework Statement

Homework Equations

The Attempt at a Solution

Homework Statement

Homework Equations

The Attempt at a Solution

 

[HallsofIvy]

It's not clear to me why you are doing that. There clearly is a dominant solution- both prisoners "tattle".