It is 7 years x 365.25 days in a year x 24 hours in a day x 60 mins in an hour x 60 seconds in a minute....
=220903200seconds
7
you have lived 409968000 seconds in 13 years 409968000 seconds
1,000,000,000 seconds or 31.688 years
11-year-olds, in any year, have lived 347,133,600 seconds.
283824000 seconds.
A minimum of 504,576,000 seconds but it depends on the time of day you were born and how many leap years you have lived through.
There are 420 seconds in 7 minutes, since 7 minutes * 60 seconds/minute = 420 seconds.
72 years is about 2,272,098,672 seconds.
12 years is 378,683,112 seconds.
25 years is 788,923,150 seconds.
47 years = 1,482,192,000 seconds
Since there are 86,400 seconds in a day and 365.25 days in a year, a 9-year old has lived at least 284,018,400 seconds.