99.9% no Kakuritsu de Oppai wo Misete Kureru Hanashi - Oneshot

[Insignis]

This somehow pissed me off from the very premise.
Just a little class here: Saying you have a 99,9% chance of getting tails at least once with 10 toin-cosses Is incorrect.
Totally WRONG.
Thats not how probability works.
Just because you have 50% of getting tail doesn't mean you will get it. You could do 1000 toin-cosses and still get just heads. Because this isn't a gacha, probabilities doent add up. It will be 50/50 for each toin-coss, and if you are unlucky you could do toin-cosses until your arm bleeds and never get tails.

No clue what you are on about. Probability to get tails at least once in 10 tosses basically means all the possible outcomes minus the single "bad" one where all 10 tosses gives you head - aka 1 minus the P for that 10 heads. Or a sum of probabilities to get at least 1, 2, 3 up to all 10 tails in those 10 tosses. Either ends up being around 0.99902 aka you do have a 99.9% chances to get a tail at least once in such a 10 coin-toss game.

Thou you are right with one thing 99.999999999999999999999999% is still not 100%, and thus you can be "unlucky" and fail 1k times in a row. Thus one thing the dude in this manga failed at is the way he thinks each toss gives him better chances to win - each toss is the same 50/50 and it give no fucks about previous tosses, so as long as he did have a 99.9% chances to win the game overall, each "stage" wasn't magically giving him better chances of wining from the per toss 50/50. He just was unlucky and failed the 50% chance thing 10 times in a row.

 

[erintesden]

No clue what you are on about. Probability to get tails at least once in 10 tosses basically means all the possible outcomes minus the single "bad" one where all 10 tosses gives you head - aka 1 minus the P for that 10 heads. Or a sum of probabilities to get at least 1, 2, 3 up to all 10 tails in those 10 tosses. Either ends up being around 0.99902 aka you do have a 99.9% chances to get a tail at least once in such a 10 coin-toss game.

Thou you are right with one thing 99.999999999999999999999999% is still not 100%, and thus you can be "unlucky" and fail 1k times in a row. Thus one thing the dude in this manga failed at is the way he thinks each toss gives him better chances to win - each toss is the same 50/50 and it give no fucks about previous tosses, so as long as he did have a 99.9% chances to win the game overall, each "stage" wasn't magically giving him better chances of wining from the per toss 50/50. He just was unlucky and failed the 50% chance thing 10 times in a row.

What I mean, was basically what you explained on your second paragraph, I probably didn't explained it well.
But yeah, Mc was too naive thinking he has his victory secured, when probability doesn't work in the way he believed. He always had 50/50 chance of winning or losing on each toin-coss and unfortunately for him, luck wasn't on his side. So he lost the ten times in a row. Though, that's assuming the game was totally fair.
As some commented, there's a chance the girl was cheating.

 

[malagigi_encantatore]

This somehow pissed me off from the very premise.
Just a little class here: Saying you have a 99,9% chance of getting tails at least once with 10 toin-cosses Is incorrect.
Totally WRONG.
Thats not how probability works.
Just because you have 50% of getting tail doesn't mean you will get it. You could do 1000 toin-cosses and still get just heads. Because this isn't a gacha, probabilities doent add up. It will be 50/50 for each toin-coss, and if you are unlucky you could do toin-cosses until your arm bleeds and never get tails.

Yup he’s completely caught in the gambler’s fallacy