expected value problem

[poopick]

Let's assume a game with three equal outcomes and a beting system that's when you win you double your bet ,if you lose you lose your bet and if its a tie you get your bet back
the EV is
0.33*betSize - 0.33*betSize = 0
but if i will use the following strategy it will change
bet 10 and if you lose you double your bet up too two times then you return to the original bet size if you win at some point you return to the original bet size if there is a tie continue with the same bet size as nothing happened
by doing this i created 4 events
1.bet 10 win 20 total 10
2.bet 10 lose 10 bet 20 win 40 total 10
3.bet 10 lose 10 bet 20 lose 20 bet 40 win 80 total 10
4.bet 10 lose 10 bet 20 lose 20 bet 40 lose 40 total -70
And the probably of them is
1.win 0.33
2.lose then win 0.33*0.33 = 0.1
3. Lose then lose then win 0.33*0.33*0.33 = 0.03
4.lose then lose then lose 0.33*0.33*0.33 = 0.03
and from that we can create EV
0.33*10+0.1*10+0.03*10-0.03*70=2.23
positive EV I'm ignoring tie outcomes because we neither wi or lose when this happens
i tried to simulate this with a python program and i got 0 EV can someone explain why this EV formula dosent work please

 

[BigBeachBanana]

First, you said

Let's assume a game with three equal outcomes and a beting system that's when you win you double your bet ,if you lose you lose your bet and if its a tie you get your bet back
the EV is
0.33*betSize - 0.33*betSize = 0
but if i will use the following strategy it will change
bet 10 and if you lose you double your bet up too two times then you return to the original bet size if you win at some point you return to the original bet size if there is a tie continue with the same bet size as nothing happened
by doing this i created 4 events
1.bet 10 win 20 total 10
2.bet 10 lose 10 bet 20 win 40 total 10
3.bet 10 lose 10 bet 20 lose 20 bet 40 win 80 total 10
4.bet 10 lose 10 bet 20 lose 20 bet 40 lose 40 total -70
And the probably of them is
1.win 0.33
2.lose then win 0.33*0.33 = 0.1
3. Lose then lose then win 0.33*0.33*0.33 = 0.03
4.lose then lose then lose 0.33*0.33*0.33 = 0.03
and from that we can create EV
0.33*10+0.1*10+0.03*10-0.03*70=2.23
positive EV I'm ignoring tie outcomes because we neither wi or lose when this happens
i tried to simulate this with a python program and i got 0 EV can someone explain why this EV formula dosent work please

It's because the sum of the probability of the 4 events doesn't add up to 1.
[math].33+.1+.03+.03 = .49 \neq 1[/math]

 

[poopick]

First, you said

It's because the sum of the probability of the 4 events doesn't add up to 1.
[math].33+.1+.03+.03 = .49 \neq 1[/math]

but any event that i will add that has to do with a tie (the missing presence) will cancel out dou to multiplication of 0

 

[BigBeachBanana]

Reply

but any event that i will add that has to do with a tie (the missing presence) will cancel out dou to multiplication of 0

Did you make sure that it adds up to 1? Also, I haven't questioned how you came up with these 4 scenarios. They seem arbitrary as they don't follow any general pattern or constraints (for example, the number of times you can bet varies between each scenario).