Apartly-full paint can has 0.52 gallons of paint left in it. (a) what is the volume of the paint, in cubic meters? (b) if all the remaining paint is used to coat a wall evenly (wall area = 15 m2), how thick is the layer of wet paint? give your answer in meters.

1 US gallon= 3.78541178 liters
a ) 0.52 gallons=1.9684 liters= 1.9684 dm³=0.0019684 m³
b ) 15 m² · x = 0.0019684 m³
x = 0.0019684 : 15 = 0.0001312 m = 0.1312 mm
A layer of wet paint is 0.1312 mm thick.
But if it is a British gallon:
1 Imperial gallon= 4.546 liters
a ) 0.52 gallons = 2.364 liters = 2.364 dm³ = 0.002364 m³ 
b ) x = 0.002364 : 15 = 0.000158 m = 0.156 mm. 

Definitely