St Nicholas 2025 P6 Maths Prelim — Paper 2 Q13b Solution

Paper 2 · Q13b · 2 marks · Volume of Cube and Cuboid

Question

For the fish tank, (b) At the end of 25 minutes, what fraction of the tank was not filled with water?

Answer: $\frac{5}{32}$

$\frac{3}{8}$ of the tank $= 48\text{ l}$, so $\frac{1}{8} = 16\text{ l}$ and the full tank $= 8 \times 16 = 128\text{ l}$. After 25 minutes the tank held 108 l, so $128 - 108 = 20\text{ l}$ was empty. Fraction not filled $= \frac{20}{128} = \frac{5}{32}$.

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