Two coins are flipped and the results are recorded. Given that one coin lands on a head, find the probability of:(adsbygoogle = window.adsbygoogle || []).push({});

a) Two heads, b) a head and a tail

Searching online is giving my answers which are not using conditional probability at all, and our teacher told us we have to use the formulas etc, but i keep getting it incorrect.

Well i haven't attempted b as i can't do a but here is my working:

Let a be the coin that lands on heads

Let b be the unknown coin

so P(B | A) = P(B and A) / P(A)

P(A) = 1/2

P(B) = 1/2

P(B and A) = 1/4

P(B | A) = 1/4 / 1/2 = 1/2 which is obviously wrong.

To be honest i think P(A) is correct but i don't know how to do P(B).

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# High school conditional probability

Loading...

**Physics Forums | Science Articles, Homework Help, Discussion**