$\frac{1}{4}$ of a tank holds 135 litres of water. What part of the tank is full if it contains 180 litres of water?
(a)$\frac{1}{6}$
(b)$\frac{1}{3}$
(c)$\frac{2}{3}$
(d)$\frac{2}{5}$
Answer
Answer (as printed): B
Explanation
Let the capacity of the tank be $x$ litres. Then, $\frac{1}{4} x=135 \Leftrightarrow x=135 \times 4=540$. $$\therefore \quad \text { Required fraction }=\left(\frac{180}{540}\right)=\frac{1}{3} .$$
Explanation as extracted from the printed page; notation may be imperfect.