If your front lawn is 18.0 feet wide and 20.0 feet long, and each square foot of lawn accumulates 1050 new snow flakes every minute, how much snow (in kilograms) accumulates on your lawn per hour? assume an average snow flake has a mass of 2.00 mg

First, we need to determine the entire area of your front line by multiplying its length times its width.
18.0*20.0 = 360.0 square feet
We can use the rate of accumulation of snow, combined with this figure, to determine how much snow accumulates on your lawn per minute.
360.0 sq ft * 1050 flakes/min/sq ft = 378,000 flakes/min
We can then use the mass of a snowflake to calculate total snow accumulation per minute.
378,000 flakes/min * 2.00 mg/flake = 756,000 mg/min
Finally, we can use this number to determine accumulation per hour.
756,000 mg/min * 60 min/hr =
45,360,000 mg/hr