The answer is:
27/03/1980 square root of 2025 = 45 (still alive and so he will be 45 years in 2025)
2025 - 45 = 1980
Cuberoot(Day) = month. Here there are two possibilities
1. cuberoot(27) = 3
2. cuberoot (8) = 2.
But we need day + month = 30. So i take day as 27 and month as 3.