Subject: General Aptitude · Chapter: Profit and Loss · Exam: 2006 · Marks: · Difficulty:
A shopkeeper advertises for selling cloth at 4\% loss. However, by using a false metre scale he actually gains 20\%. What is the actual length of the scale?
(a)70 cm
(b)75 cm
(c)80 cm
(d)90 cm
Answer
Answer (as printed): C
Explanation
Let the percentage deduction in weight be $y \%$. Then, $\frac{y-4}{100-y} \times 100=20 \Rightarrow \frac{y-4}{100-y}=\frac{1}{5}$ $$\Rightarrow 5 y-20=100-y \Rightarrow 6 y=120 \Rightarrow y=20 .$$ Hence, for a metre, length used = (100-20)\% of 1 m = 80\% of 100 cm = 80 cm.
Explanation as extracted from the printed page; notation may be imperfect.