If you 30,400 people died in 2015, how many deaths per hour

well, let's assume you haven't been dead for 3 years then, 30,400 a year, expressed as a unit rate per hour?

assuming a year has 365 days.

a day has 24 hours, therefore a year will have 365*24 hours.

so 30400 per year, will be 30400 / (365*24) per hour, namely about 3.47031963, which we can round up to about 3 deaths per hour.