If 3⁄4 gallons of water come out of a hose in 15 minutes, to calculate the rate of water that comes out in an hour (60 minutes), we will use the expression;
3/4 gallons = 15 minutes
x gallons = 60minutes
cross multiply
15x = 3/4 * 60
15x = 180/4
15x = 45
x = 45/15
x = 3/1
x = 3:1
Hence the water rate in gallons per hour is 3 gallons per hour