simple math question

[ThaWoj]

If i flip a coin 3 times, my chances of guessing all 3 correctly is 12.5%, right?

And guessing 2 out of 3 is 25%?

[tto827]

3 out of 3 is .5x.5x.5 =.125 or 12.5% as you said

Chances of guessing 2 and only 2 correct out of 3 is 3/8 or 37.5%

Chances of guessing two or more correct is 4/8 or 50%

[ThaWoj]

Where does 3/8 and 4/8 come from? Thx

[pavyracer]

There is also a chance of landing upright or getting lost in a manhole or a bird picking it up in the air. So you have to add +/- 0.01% to the above probabilities.

[tto827]

Where does 3/8 and 4/8 come from? Thx

Easiest way to do it with this small of a sample is just list all possible outcomes.

Assuming you always pick heads
HHH
HHT
HTT
HTH
TTT
TTH
THH
THT

Red ones are 2 correct and only two correct, green is all 3 correct (so the or more part of 2 or more0

[ThaWoj]

Now it makes sense thx. I was trying to use my example for blackjack (i know its a less than 50% chance of winning a hand and i didnt account for pushes).

[mynameismud]

tto is a math prodigy.

[sweethook]

you win again

[Cheme82]

If i flip a coin 3 times, my chances of guessing all 3 correctly is 12.5%, right?

And guessing 2 out of 3 is 25%?

Use a binomial calculator bro. You can find whatever combination you want and since you are talkig about blackkjack, you can use whatever probabilit you actually have (less than 50%).

http://www.vassarstats.net/textbook/ch5apx.html

[ThaWoj]

Thanks

[Marigold HD]

25%