A fair coin is tossed 4 times. Given that each of the first 3 tosses land tails up, what is the probability that all 4 tosses land tails up?

i think ...

isn't it
3/4?

1/2.. Same as a single coin toss. The odds of each toss are independent of what went before.

oh yeah duh haha

it doesn't matter what was before there're two choices haha i remember now :]
hey answer my question!!

I did answer your question

To find the probability that all 4 tosses land tails up, given that each of the first 3 tosses land tails up, we can use the concept of conditional probability.

The probability of an event A occurring, given that event B has occurred, is denoted as P(A|B), and it is calculated using the formula:

P(A|B) = P(A ∩ B) / P(B)

Here, A represents the event "all 4 tosses land tails up" and B represents the event "each of the first 3 tosses land tails up".

Now, let's find the probabilities required for the formula:

P(A ∩ B) denotes the probability that both events A and B occur simultaneously. In this case, it is the probability that all 4 tosses land tails up, which is (1/2)^4 = 1/16, since there are 2 equally likely outcomes (tails or heads) for each toss.

P(B) denotes the probability of event B occurring. Given that each of the first 3 tosses land tails up, the probability of getting tails on each individual toss is (1/2)^3 = 1/8.

Substituting these values into the formula, we have:

P(A|B) = (1/16) / (1/8) = 1/2

Therefore, the probability that all 4 tosses land tails up, given that each of the first 3 tosses land tails up, is 1/2 or 50%.