we have to convert the rate from pints per minute to gallons per hour
1 pint = 0.125 gallon
1 minute - 1/60 hours
we can write 15 pints per minute as
15 pints / 1 minute
to convert pints to gallons we have to multiply by 0.125 gallon/pint
to convert minutes to hours we have to multiply by 1/60 hours/minute

=

rate is 112.5 gallons/hour