Chapter 8.1, Problem 7WE

To determine

To solve the direct variation.

Answer to Problem 7WE

The solution is $p=50$ .

Explanation of Solution

Given information:

The given statement is:

“If $p$ is directly proportional to $r-2$ , and $p=20$ when $r=6$ , find $p$ when $r=12$ .”

Calculation :

Since, $p$ is directly proportional to $r-2$ .

The solution can be obtained by:

  $\begin{array}{l}\frac{p_1}{\left(r_1-2\right)}=\frac{p_2}{\left(r_2-2\right)}\\ \frac{20}{\left(6-2\right)}=\frac{p_2}{\left(12-2\right)}\\ \frac{20}{4}=\frac{p_2}{10}\\ p_2=\frac{20\times 10}{4}\\ p_2=50\end{array}$

Hence, the solution is $p=50$ .