Tell whether the table represents inverse variation.
If so, write the inverse equation and solve for y 
when x=4. Show work that supports your conclusions.

The Table
Amperes (X)      Ohms  (y)  
   310             .04             
   124              .1
   62               .2 
  15.5              .8

We will start with the inverse equation



and substitute in the values and see if the k remains constant:



We substitute x = 310 and y = .04 and solve for k



We multiply both sides by 310



We substitute x = 124 and y = .1 and solve for k



We multiply both sides by 124



So far, so good.  k is so far stayed constant
at 12.4.  But we must check the others too.
Substitute x = 62 and y = .8 and solve for k



Multiply both sides by 62



k is still 12.4

Substitute x = 15.5 and y = .8 and solve for k



Multiply both sides by 15.5



Since the constant k remained constant for
all the given values, we can assume that
the table represents inverse variation.

So we write the inverse equation



with k = 12.4

 

and solve for y when x=4.





Edwin