If you roll a 6 sided die, what is the chance of rolling a 3 or a 5?

Question

praetorian.10 · Answer

this seems pretty mathematical bro

praetorian.10 · Answer

the answer is 2/6

praetorian.10 · Answer

which can be reduced to 1/3

praetorian.10 · Answer

so one third of a chance

praetorian.10 · Answer

ps. thanks for the meddal

anonymous · Answer

@idekanymore Just to elaborate, the key here is the "or". This means the probabilities are independent of each other and are added together. This is because to fulfill the desired number you only need to roll one.  Now, if you had to roll a 5 AND a 6, that would mean that you would multiple the odds, so$$(1/6)^{2}=1/36$$

The odds are worse because if you roll a 4 on the first roll you are done. You have to roll roll a 5 or a 6 on the first roll, and then roll the next number. So if the first roll was a 5 then your second roll would have to be a 6.

praetorian.10 · Answer

Lol i have no idea how you got a medal for that business it totally confused me!

praetorian.10 · Answer

Was i right though? provided he only needs one of the numbers not both?

anonymous · Answer

@PRAETORIAN.10 Let me try to simplify, and yes you were right.

If you have to get both numbers, you have more ways for it to go wrong. One the very first roll you have a 5/6 chance of not getting the right number and failing, then if you get the 1/6 chance of the correct number you still have a 5/6 chance of not getting the second number. While if you have an "or" situation you you have the same you have a 4/6 chance of not getting the one of the right numbers. 

I think that helps explain why the odds are worse for AND conditions, and I am not sure I can explain it well enough on here as to why for AND you multiple and OR you add.

praetorian.10 · Answer

you got another medal! that was even more indecipherable than the first time. LOL!

anonymous · Answer

@PRAETORIAN.10 I don't think it gives you another medal, I think it just indicates the metal to all posts made in a thread for a user that gets a medal. Not sure why really, seems like an extremely confusing thing to do.

Hmm, if it is confusing then I will not post more, but I just wanted to give the OP the reasoning behind the answer, if he/she choses to read it. However, if it is confusing @idekanymore please don't bother to read it.