Question 138204
To express the relationship of x and y, you write the equation of variation:
{{{x = ky}}} This says that x varies directly with y.  The k is called the constant of variation and to find its value, you will need to be given a value of x and the corresponding value of y. Your problem provides these values:
 x = 5, and y = 40.
So you substitute these into the equation and solve for k.
{{{5 = k(40)}}} Divide both sides by 40.
{{{k = 5/40}}} Simplify the fraction.
{{{k = 1/8}}} This is the value of the constant of variation, k.
Now you can write the final equation of variation:
{{{x = (1/8)y}}}