Bayesian probability problem

martinl

Member
There are 2 bags. Bag A contains 100 gold coins. The other bag B contains 50 gold coins and 25 silver coins.
Suppose John chose a bag and then picked 1 coin from within, the coin was a gold coin, what's the probability
that he picked bag A ?
The answer is 0.5833 using Bayes' Theorem.

What if instead of picking only 1 coin, John picked 2 coins and both coins were gold coins. Now
what's the probability that he picked bag A ?

Does anyone know how to calculate this?

Last edited:

Dason

Can you show how you would calculate the probability when picking just one coin?

Dason

Can you show how you would calculate the probability when picking just one coin?

martinl

Member
Can you show how you would calculate the probability when picking just one coin?
It's calculated in this way:
P(Bag A | gold coin) = (0.5 x 1) / (150/175)