You can't as a formula can't detect a colour, you either have to test for the condition that the cell is coloured based on or use a VBA function (and even then it depends whether your cell is coloured by fill colour or conditional formatting).
Try putting the code below in a regular module, then use the formula below.
Please note that it will only pick up the standard yellow, if they don't use it then we can change the code so that it is based on one of the cells fill color.
Function ColorFunction(rRange As Range)
Dim rCell As Range, vResult
For Each rCell In rRange
If rCell.Interior.ColorIndex = 6 And rCell.Value = "satisfactory" Then vResult = 1 + vResult
ColorFunction = vResult