Safe wall percentage

The safe is 100 cm high, 80 cm wide, and 60 cm deep. Its internal space has a volume of 168 liters.
What percentage of the total volume of the safe is occupied by the walls of the safe?

Final Answer:

p =  65 %

Step-by-step explanation:

$$\begin{gathered} a=100\text{cm}\to \text{dm}=100:10\text{dm}=10\text{dm} \\ b=80\text{cm}\to \text{dm}=80:10\text{dm}=8\text{dm} \\ c=60\text{cm}\to \text{dm}=60:10\text{dm}=6\text{dm} \\ {V}_1=a\cdot b\cdot c=10\cdot 8\cdot 6=480{\text{dm}}^3 \\ {V}_2=V_1\to \text{l}=V_1\cdot 1\text{l}=480\cdot 1\text{l}=480\text{l} \\ {V}_3=168\text{l} \\ {V}_4=V_2-V_3=480-168=312\text{l} \\ p=100\cdot \frac{V_4}{V_2}=100\cdot \frac{312}{480}=\frac{100\cdot 312}{480}=\frac{31200}{480}=65\% \end{gathered}$$

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