NCERT Example 17 - Probability
Question: Three identical boxes I, II, III each contain two coins: I has two gold coins, II has two silver coins, III has one gold and one silver. A box is chosen at random and a coin drawn from it is gold. Find the probability that the other coin in the box is also gold.
Answer: 2/3.
Full step-by-step NCERT solution with diagrams on Something by Zero.