Answer:
47628 kg/hr
Step-by-step explanation:
Total area = 18*20 =360 ft^(2)
no .of snowflakes per minute = 1050*360 =378000
mass of snowflakes per minute = 378000*2.1*10^(-3) =793.8 kg/min
mass accumulated per hour = 793.8kg/min * 60min/hr =47628 kg/hr