10% is small enough that it does not matter for these types of informal conversational scenarios, and in cases where it does, do a proper conversion.
/2 = 1500 .1 = 150 = 1500 - 150 = 1350kg
Google's result: 1360.777kg
10% is small enough that it does not matter for these types of informal conversational scenarios, and in cases where it does, do a proper conversion.