SOLUTION: Our topic is about Postulates. A coin is tossed four times. a)List of all the possible outcome b)Find the probability that no tail turns up c)Find the probability that exac

Question 1128274: Our topic is about Postulates.
A coin is tossed four times.
a)List of all the possible outcome
b)Find the probability that no tail turns up
c)Find the probability that exactly one head turns up
d)Find the probability that at least 3 tails turn up
Thank you in advance.
Answer by Quadratic1600(28) (Show Source): You can put this solution on YOUR website!
Hi
I will do my best!!
a) Ok so possible outcomes are
H H H H
H H H T
H H T H
H H T T
H T H H
H T H T
H T T H
H T T T
T H H H
T H H T
T H T H
T H T T
T T H H
T T H T
T T T H
T T T T

H is for heads/T is for tails
b) Ok so this quite hard (for me anyway!!)
Ok so for
1st toss - 0.5 chance either way
2nd toss - 0.5 chance either way
3rd toss- 0.5 chance either way
4th toss - 0.5 chance either way
So we are looking for the probability that no tails turn up so we would do
0.5 x 0.5 x 0.5 x 0.5 = 0.0625 = 1/16
I think that is correct!
c)
Ok to find the probability that exactly one head turns up
it doesn't matter on which toss the coin does turn up - the answer will be the same whether it was the first toss or the final toss!
Ok so
if we go back to all our possible outcomes then we can note that only 4 out of the 16 have only 1 head so 4 in 16 = 25% at least I think it is!!
d) Right so once we know how to work out c then this becomes easier
By looking at the list of possible outcomes we can find out how many contain 3 or more Ts. So by looking at the list we now know that there is a 5 in 16 chance.
I hope this helps - Just use the list of possible outcomes to find out the probability!

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