If your front lawn is 25.0 feet wide and 20.0 feet long, and each square foot of lawn accumulates 1350 new snowflakes every minute, how much snow, in kilograms, accumulates on your lawn per hour? Assume an average snowflake has a mass of 1.90 mg.

Explanation:

calculate area of lawn

25  * 20  =  500  sq ft

calculate how many flakes fall per minute

500  *  1150  =   575 , 000  flakes/minute

convert per minute rate to per hour rate

575 , 000  * 60  = 34 ,500 , 000  flakes/hour

now you know how many flakes feel in that one hour so we can now weigh them

34 , 500 , 000  / 1.8  = 19 , 166 , 667  mg (rounded)

convert to kilograms

19 , 166 , 667 /  100 , 000  = 19.17  kg (rounded)