15
There are 60 seconds in one minute.
One week = 1,209,600 half-seconds.
6720
5,400 seconds are in 1 hour 30 minutes.
90 seconds
3600 t
90
9,000 seconds.
There are: 90*60 = 5,400 seconds
There are 86,400 seconds in one day. There are 1,440 minutes in one day.
15 min.