Answer: The required constant of inverse variation is 37.5 and equation for the inverse variation is

Step-by-step explanation: We are given to find the constant of inverse variation and to write an equation for the following inverse variation :
y = 5 when x = 7.5.
Let k denote the constant of inverse variation.
According to the given information, we can write
![y\propto(1)/(x)\\\\\\\Rightarrow y=(k)/(x)~~~~~~~~~~~~~~~~~~~~~~~~~~~[\textup{k is the constant of inverse variation}]\\\\\Rightarrow yx=k~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)](https://img.qammunity.org/2017/formulas/mathematics/high-school/zmndzacwnlkllknlheis17kxht9l8dms52.png)
When y = 5, x= 7.5, then from equation (i), we get

Substituting the value of k in equation (i), we arrive at

Thus, the required constant of inverse variation is 37.5 and equation for the inverse variation is
