How many cans of paint are needed to cover an area of 2,200 square units if one can of paint covers an area of 400 square units? 12 of 60

If one can of paint covers 400 square units, then just divide the total coverage needed by the coverage from 1 can of paint.
2200 / 400 = 5.5
This means 5.5 cans are needed.
But since you can't buy half of a can of paint, that means 6 cans are needed.