Two coins are thrown. One of them is guaranteed to be head. What

>>8946945
In other words, does it matter that you now know that the "first" coin you picked is heads and the and the probability ups to 0.5 given that you do not know whether you were given the first or second coin?

When it is guaranteed to be heads, 1/2.
When you are given the coin afterwards and it has resulted in heads, 1/4.

In the first, you do not need to factor the probability of the first coin landing heads/tails, because it has a set value of heads, hence 1/2.

In the second one, the coin is flipped and only given to you if heads results, hence from all attempts this would be expected to occur in some 1/4 of cases.

>>8946945
1/3

>>8946945
1. (1/2)

2. P( A | B) = P(AB)/P(B) = (1/4)/(1/2) = (1/2)

1/3
1/2

>>8947036
This

>>8947036
Now here's the point I don't get.
You don't know which of these two coins you are getting (aka the first or the second coin), so you are still getting one of three possible outcomes, namely 01, 10 and 11. How is the the probability now 0.5 rather than 1/3?

It's tricky just because pf retarded semantics. For the first 1 you only know that at least 1 is going to be heads, but at least one has different possibilities than knowing one already is heads. Because at least one can be (1,1) (1,0) (0,1). So yoy have P(at least 1)=3/4. So P(2 heads| at least 1 is P(at least 1| 2 heads)P(2 heads)/P(at least 1)= 1/4 / 3/4 = 1/3. For the second one you know 1 and you know which one it is so you don't have at least one, your information changes more drastically and you have p(2 head|1head)=P(2 heads and 1 head)/(P(1 head)= 1/4/(1/2)=(1/2). In this case the events are independent so, it's what ypu would expect.

This is a restatement of the boy or girl paradox

>>8947196
I don't ger this """"paradox""""" it arises only if you start asking HOW do ypu know at least one is a boy? There are a lot of probability questions that use magic and bs to illustrate problems. Why not jus add, "a magical gypsy told you AT least one is a boy?"

>>8946945
1/3 for both

every piggot who didn't answer properly should jsut be auto redirected to pol when they click sci

>>8947003
Except the probability of at least one of them being heads is 3/4

>>8948590
The way the problems are given in the OP, the probability of at least one being heads is 1, in both cases.

>>8946945
>Two coins are thrown.One of them is guaranteed to be head. What is the probability of both being head?

if this means that one set coin inpartiuclar isalways head, e.g. the rightcoin is lways head, thenit is a half

if however "one of them" doesn't refer to a particular , set coin, then the probability is 1/3

>Two coins are thrown.
>You are given one of these coins and it is head. What is the probability of both being head?
depends how the one coin was given.
if it is decided before hand that always the coin marked "2" is given, and the coins are then flipped, and you find out that coin two happens tobe heads, then the probability that the coin happens to be heads is a half.

equally,if the coin given to you is selected at random without regard to whether the coin is heads or tails, thenthe probability of the other coin being heads is also half.

However if the coin giver will only give you a coin if it is head and could give you either of the coins, then the probability that both coins are head is 1/3


THIS COVERS ALL CIRCUMSTANCES AND OBJECTIVELY SOLVES THE PROBLEM