Quantity I: At marriage, average of Ashish and wife = 25, so sum = 50. 4 years later, Ashish + wife + son's average = 17, so sum = 51. (Ashish+4)+(wife+4)+(son) = 51. Ashish+wife+son = 43. At marriage, Ashish+wife = 50, so son = 43-50 = -7 (not yet born). Let Ashish's age at marriage = x, wife = 50-x. After 4 years: Ashish = x+4, wife = 54-x. Total people for average: (x+4)+(54-x)+son = 58+son = 51 implies son's age = -7 (not born). Average is of 2 people (Ashish and son): (x+4+son)/2 = 17. Son's age = 30-x. At marriage: Ashish = x, wife = 50-x. 4 years later: Ashish+son average = 17. If son not born 4 years after, then average of Ashish and wife was (x+4+54-x)/2 = 29. Contradiction. Let's solve: (x+4)+(50-x+4)+son = 51+son. Average of Ashish and son (2 people): (x+4+son)/2 = 17, so x+4+son = 34, son = 30-x. 4 years after marriage, son born so son ≥ 0, so 30-x ≥ 0, x ≤ 30. At marriage x+(50-x) = 50, ages positive. Quantity II: Average of Rana, Nishant, Yash = average of Rana and Yash, so Nishant = (Rana+Yash)/2. Nishant = 27, so Rana+Yash = 54. Rana is youngest, so Rana < 27 < Yash. Rana+Yash = 54, Rana < Yash. Integer ages satisfying: Rana < 27. If Rana = 26, Yash = 28. If Rana = 25, Yash = 29. Minimum Rana age with Yash > Rana: Rana can range. Without more constraints, Rana could be 1 to 26. Assuming reasonable adult age range and typical problems, likely Rana = 26. But Quantity I: x ≤ 30 from earlier, also at marriage typically ≥ 21. If x = 26, then Quantity I = 26. This matches.