This calculation about it first, you said that the construction area of ​​120 square meters, the actual area of land should be 110 , according to the most basic form is an area of ​​operations is multiplied by 3.2, there are some companies that are multiplied by 3.5, this is too much , so 3.2 is reasonable, so its area is 350 square meters of the second wall, mixing paint brush for each L of 6 square meters twice, then you need to 58L third-base paint mixed Duishui 10% , fourth course is the real need 52L of paint , the paint on the market now are basically to 4.5 or 5 liters the barrel, so it has to end 10 a barrel , paint bucket with 5