The room

The room has a cuboid shape with dimensions: length of 50m and width of 60 dm, and height of 300 cm. Calculate how much this room will cost (a floor is not painted) if the window and door area is 15% of the total area and 1m² costs 15 euros.

Correct answer:

x =  8109 Eur

Step-by-step explanation:

$$\begin{gathered} a=50\text{m} \\ b=60\text{dm}\to \text{m}=60:10\text{m}=6\text{m} \\ c=300\text{cm}\to \text{m}=300:100\text{m}=3\text{m} \\ S=a\cdot b+2\cdot (a+b)\cdot c=50\cdot 6+2\cdot (50+6)\cdot 3=636{\text{m}}^2 \\ {S}_1=(1-15/100)\cdot S=(1-15/100)\cdot 636=\frac{2703}{5}=540.6{\text{m}}^2 \\ x=15\cdot S_1=15\cdot 540.6=8109\text{Eur} \end{gathered}$$

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