Step-by-step explanation:
42 people per minute
how many minutes for 15000 people ?
well, how often does 42 fit into 15000 ?
15000/42 = 357.1428571... minutes
and since we want to bring in everyone of the 15000, we have to count the fraction of the last minute as minute.
so, we have 358 minutes.
and that is in hours, as 1 hour = 60 minutes
358/60 = 5.9... hours
so, the rounded answer is 6 hours.