Aquarium filling

The aquarium, with a length - of 40 cm, width - of 24 cm, and height of 27 cm, is filled to 2/3. How much water do we need to add to be filled to 8/9?

Final Answer:

x =  5.76 l

Step-by-step explanation:

$$\begin{gathered} a=40/10=4\text{dm} \\ b=24/10=\frac{12}{5}=2.4\text{dm} \\ c=27/10=\frac{27}{10}=2.7\text{dm} \\ V=a\cdot b\cdot c=4\cdot 2.4\cdot 2.7=\frac{648}{25}=25.92\text{l} \\ x=V\cdot (8/9-2/3)=25.92\cdot (8/9-2/3)=\frac{144}{25}\text{l}=5.76\text{l} \end{gathered}$$

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