Subject: General Aptitude · Chapter: Ratio and Proportion · Exam: 2007 · Marks: · Difficulty:
If $x$ is inversely proportional to $y$ and $y$ is proportional to $z$, then $x z$
(a)is proportional to $y$
(b)is inversely proportional to $y$
(c)is a constant
(d)is proportional to $y^{2}$
Answer
Answer (as printed): C
Explanation
$x \alpha \frac{1}{y}$ and $y \alpha z \Rightarrow x=\frac{k}{y}$ and $y=m z$ for some constants $k$ and $m$. $$\therefore x z=\frac{k}{y} \times \frac{y}{m}=\frac{k}{m}=\text { constant. }$$
Explanation as extracted from the printed page; notation may be imperfect.