Question

If $x\text{and}y$ are directly related, then, find $l,m\text{and}n$.

$x$	$10$	$6$	$l$	$15$
$y$	$5$	$m$	$7$	$n$

• A. $m=3l=14n=7.5$
• B. $m=12l=14n=7.5$
• C. $m=3l=21n=7.5$
• D. $m=3l=14n=30$

Answer 1

The correct option is A $m=3l=14n=7.5$

Given,
$x\text{and}y\text{are directly related}$.
$\therefore \frac{x_1}{y_1}=\frac{x_2}{y_2}$

$\left(i\right)$
Let,
$x_1=10$
$y_1=5$
$x_2=6$
$y_2=m$
$\Rightarrow \frac{10}{5}=\frac{6}{m}$
$\Rightarrow m=\frac{30}{10}=3$

$\left(ii\right)$
Let,
$x_1=10$
$y_1=5$
$x_2=l$
$y_2=7$
$\Rightarrow \frac{10}{5}=\frac{l}{7}$
$\Rightarrow l=\frac{70}{5}=14$

$\left(iii\right)$
Let,
$x_1=10$
$y_1=5$
$x_2=15$
$y_2=n$
$\Rightarrow \frac{10}{5}=\frac{15}{n}$
$\Rightarrow m=\frac{75}{10}=7.5$