Question

If I varies inversely with R and I = 0.25 when R = 18, which equation should be used to show this relationship?

Answer 1

Inverse relationships are of the form xy=k or if you prefer  y=k/x so to find the constant we can say:

18(0.25)=k=4.5

So you could say: IR=4.5 or I=4.5/R