The average age of a husband – wife and their son was 42 years. The son got married and exactly after 1 year child was born to them. When the child became 5 years old, the average age of the family became 36 years. What was the age of bride at the time of marriage?

Initial family: husband, wife, son. Average age = 42, so total = 3 × 42 = 126. Son marries → family now has 4 people. After 1 year, child is born → 5 people. When child is 5 years old, 6 years have passed since son's marriage. New total age = 126 + 6 + (bride's age + 5) = 5 × 36 = 180. So bride's age + 131 = 180, bride's age at that time = 49. At marriage (6 years earlier), bride was 49 - 6 = 25 years old. Track time passage and total age changes carefully.