Bayesian probability problem

#1
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?
 
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