Odds question from my friend

[B Dids]

friend of Dids sez:

i'm either having a dumb math day or somethign else.... is there anyone online you could ask that could explain to me why the numbers in the "outs" table for turn AND river aren't just the two other columns added up?

http://www.online-poker-rules.net/odds-draw-cards.html

for example:

Outs Turn % River % Turn or River
20 42.6 43.5 67.5%

i think that the turn or river column should have 86.1

[BruceZ]

[ QUOTE ]
friend of Dids sez:

i'm either having a dumb math day or somethign else.... is there anyone online you could ask that could explain to me why the numbers in the "outs" table for turn AND river aren't just the two other columns added up?

http://www.online-poker-rules.net/odds-draw-cards.html

for example:

Outs Turn % River % Turn or River
20 42.6 43.5 67.5%

i think that the turn or river column should have 86.1

[/ QUOTE ]

The 43.5% only applies to the times you miss on the turn, which is 100% - 42.6% .

42.6% + (100% - 42.6%)*43.5% = 67.5%.

[kyro]

give your friend this example.

You flip a coin. The odds of it landing heads the first flip is 50%. The odds of it landing heads the second flip is 50%. Are the odds you get heads on the first OR second flip 100%? Hopefully that will clear it up.