Question:
Mark (✓) against the correct answer:
x and y vary directly. When x = 3, then y = 36. What will be the value of x when y = 96?
(a) 18
(b) 12
(c) 8
(d) 4
Solution:
(c) 8
$x$ and $y$ var $y$ directly.
Then $x=k y$, where $k$ is the constant of proportionality.
$\Rightarrow k=\frac{x}{y}$
Now, $\frac{3}{36}=\frac{x_{1}}{96}$
$\Rightarrow \frac{96 \times 3}{36}=x_{1}$
$\Rightarrow 8=x_{1}$
$\therefore$ Value of $x=8$