- #1
peripatein
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Hi,
A coin is tossed three times. I am asked for the probability that EITHER the first toss yields heads, OR the second toss yields tails, OR the third yields heads. I am expected to use De Morgan's Laws but am not sure how to define the events the themselves. I'd appreciate some guidance.
I have found the reuested probability using the following table
First toss: HTT
Second toss: HTH
Third toss: TTH
to be 3/8.
But how may I show that rigorously? Mind you, we haven't dealt with multiplication of probabilities (so (1/2)3 for each case, let's say, would not be legit). We have hitherto only dealt with De Morgan's Laws, P(AUB)=P(A)+P(B)-P(A and B), and P(AUBUC)=P(A)+P(B)+P(C)-P(A and B) - P(B and C) - P(A and C) + P(A and B and C).
As mentioned, I'd appreciate your assistance.
Homework Statement
A coin is tossed three times. I am asked for the probability that EITHER the first toss yields heads, OR the second toss yields tails, OR the third yields heads. I am expected to use De Morgan's Laws but am not sure how to define the events the themselves. I'd appreciate some guidance.
Homework Equations
The Attempt at a Solution
I have found the reuested probability using the following table
First toss: HTT
Second toss: HTH
Third toss: TTH
to be 3/8.
But how may I show that rigorously? Mind you, we haven't dealt with multiplication of probabilities (so (1/2)3 for each case, let's say, would not be legit). We have hitherto only dealt with De Morgan's Laws, P(AUB)=P(A)+P(B)-P(A and B), and P(AUBUC)=P(A)+P(B)+P(C)-P(A and B) - P(B and C) - P(A and C) + P(A and B and C).
As mentioned, I'd appreciate your assistance.