The tank

The tank is full up to 4/5 of the total height and contains 240 hl of water. The area of the base is 6 square meters. What is the height of the tank?

Correct answer:

h =  5 m

Step-by-step explanation:

$$\begin{gathered} V=240\text{hl}\to {\text{m}}^3=240:10{\text{m}}^3=24{\text{m}}^3 \\ S=6{\text{m}}^2 \\ \frac{4}{5}{V}_2=V \\ {V}_2=V\cdot \frac{5}{4}=24\cdot \frac{5}{4}=\frac{24\cdot 5}{4}=\frac{120}{4}=30{\text{m}}^3 \\ h=V_2/S=30/6=5\text{m} \end{gathered}$$

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