Question:
If x and y are directly proportional, find the values of x1 , x2 and y1 in the table given below:
Solution:
Since $x$ and $y$ are directly propotional, we have:
$\frac{3}{72}=\frac{x_{1}}{120}=\frac{x_{2}}{192}=\frac{10}{y_{1}}$
Now, $\frac{3}{72}=\frac{x_{1}}{120}$
$\Rightarrow x_{1}=\frac{120 \times 3}{72}=5$
And, $\frac{3}{72}=\frac{x_{2}}{192}$
$\quad \Rightarrow \quad x_{2}=\frac{3 \times 192}{72}=8$
And, $\frac{3}{72}=\frac{10}{y_{1}}$
$\Rightarrow y_{1}=\frac{72 \times 10}{3}=240$
Therefore, $x_{1}=5, x_{2}=8$ and $y_{1}=240$