Conditional Formatting in Numbers...

I'm trying to put a formula into numbers that would allow me to change the colour of the text in one box if it is equal to or less than 3x the contents of another box.

Here's an example:

In cell I3 is a figure which is a multiple of millions. In this case 0.40, meaning 400,000.

In cell K3 is a figure which is also a multiple of millions. In this case 0.10, meaning 100,000.

I need the figure in cell K3 to turn green if it is equal to or less than 3x the contents of cell I3 (i.e. 1.20 or less). If on the other hand it is greater than 3 times the content of cell I3 I need it to turn red.

A friend of mine has worked out how to do this using Excel, but I can't seem to bring this through to Numbers.

Any ideas?