Room wallpaper calculation

How many square meters of wallpaper will we need to cover the walls of a room with dimensions of 3 m and 4 m if the room height is 2.5 m? A door with dimensions of 90 cm and 2 m leads to the room. There is one window 1 m wide and 1.5 m high.

Final Answer:

x =  31.7 m²

Step-by-step explanation:

$$\begin{gathered} a=3\text{m} \\ b=4\text{m} \\ c=2.5\text{m} \\ {x}_1=90\text{cm}\to \text{m}=90:100\text{m}=0.9\text{m} \\ {y}_1=2\text{m} \\ {x}_2=1\text{m} \\ {y}_2=1.5\text{m} \\ {S}_1=x_1\cdot y_1=0.9\cdot 2=\frac{9}{5}=1.8{\text{m}}^2 \\ {S}_2=x_2\cdot y_2=1\cdot 1.5=\frac{3}{2}=1.5{\text{m}}^2 \\ x=2\cdot (a+b)\cdot c-S_1-S_2=2\cdot (3+4)\cdot 2.5-1.8-1.5{\text{m}}^2=31.7{\text{m}}^2 \end{gathered}$$

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