11. A man marries his widow's sister.

How is this possible?

Answer: see below

12. A man marries his widow's sister.

How is this NOT possible?

13. 9 9 9 9 9 9

How can you make one hundred using only six nines?

ANSWERS:

11. He married the sister first, then he married the wife before he died, making her a widow.

12. Dead men can't get married.

13. 99+ (99 divided by 99) = 100