A man was so bothered by his wife's mother and brother that he opted for divorce. He remarries another woman, only to discover that his mother-in-law and brother-in-law remain the same. Seeking relief, he divorces once again, this time resolving to stay single. Nonetheless, he has the same brother-in-law.
How is this possible?
(In reply to re: Full solution
1) I agree that Dej Mar has already fully explained the brother-in-law
2) We also need to account for the same mother-in-law in two different marriages. The simplest explanation is that the first two wives are sisters.
3) In which case, we can infer from the problem that the brother-in-law is also brother to the second wife, since the problem says the the brother-in-law is brother to the first wife. Since we have already explained the brother-in-law, I agree with brianjin that this is a gratuitous (albeit available) inference.