Average age is 12 years and 3 months
1 year is having 365 days (assuming only in leap year)
1 day is having 24 hour
1 hour is 60 min
1 min is 60 second
Now doing all these in reverse order,
1 hour = 60 x 60 second
1 day = 24 × 60 × 60 second
1 year = 365 × 24 × 60 × 60 second
So, 12 year = 12 × 365 × 24 × 60 × 60 second = 378432000 sec
1 months = 30 days
3 months will be 3 × 30 days
= 3 × 30 × 24 × 60 × 60 second = 7776000 sec
12 years and 3 months = 378432000 + 7776000
= 386208000 second
