Karan was born 3 years after his parents' marriage. His father is 6 years older than his mother but 26 years older than Karan, who is 12 years of age as of today. At what age did his mother get married?

The mother married at 17 years.

Karan is 12; his father is 26 years older, so father = 38.

Mother is 6 years younger than father, so mother = 32 now.

Karan was born 3 years after marriage, so marriage was 12 + 3 = 15 years ago.

Mother's age then = 32 - 15 = 17.

Method: work back the years to the wedding.