since nap time averages 3 hrs and can vary by 30mins then nap time = 3 + 0.25
since night time sleep averages 12hrs and van vary by 30 minutes then night time sleep = 12+ 0.25
minimum nap and night time sleep = 2.75+ 11.75=14.5hrs
max nap and night time sleep= 3.25+12.2= 15.5hrs
nap and night time sleep = 15+ 0.5 hrs
total sleep time averages 15hrs and can vary by 1 hr (1/2 hr above or below 15 hrs)
hope this helped if not I'm sorry
