Room painting cost

In the block-shaped room, the floor has dimensions of 4 m and 3.5 m. The volume of this room is 35 m³. How much will it cost to paint this room if we pay €1.2 for 1 m² of paint (remember that we will not paint the floor)?

Final Answer:

x =  61.8 Eur

Step-by-step explanation:

$$\begin{gathered} a=4\text{m} \\ b=3.5\text{m} \\ V=35{\text{m}}^3 \\ {S}_1=a\cdot b=4\cdot 3.5=14{\text{m}}^2 \\ c=V/S_1=35/14=\frac{5}{2}=2.5\text{m} \\ S=c\cdot 2\cdot (a+b)+S_1=2.5\cdot 2\cdot (4+3.5)+14=\frac{103}{2}=51.5{\text{m}}^2 \\ p=1.2{\text{Eur/m}}^2 \\ x=p\cdot S=1.2\cdot 51.5=61.8\text{Eur} \end{gathered}$$

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