Two sides paint

The door is a rectangle with dimensions of 260cm and 170cm. How many cans of paint will be needed to paint this door if one can of paint cover 2m² of the area? We paint the doors on both sides.

Correct answer:

n =  5

Step-by-step explanation:

$$\begin{gathered} a=260\text{cm}\to \text{m}=260:100\text{m}=2.6\text{m} \\ b=170\text{cm}\to \text{m}=170:100\text{m}=1.7\text{m} \\ {S}_1=a\cdot b=2.6\cdot 1.7=\frac{221}{50}=4\frac{21}{50}=4.42{\text{m}}^2 \\ {S}_2=2\cdot S_1=2\cdot 4.42=\frac{221}{25}=8\frac{21}{25}=8.84{\text{m}}^2 \\ {S}_3=2{\text{m}}^2 \\ n=\lceil S_2/S_3\rceil =\lceil 8.84/2\rceil =5 \end{gathered}$$

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