2010. 4. 14. · Your ETG's then, will peak around 9PM. Peak number can range, and EtG per drink also fall under a fairly wide range, but IMHO it should be safe to assume 15,000 ETG per drink - so that's 180,000. Every three hours (at the most) your ETG count will be cut in half. So let's walk through this (some calculations are approximate): 9PM Friday 180,000. Expression - the formula to be used for the calculation to be performed. For shortness the rasters should be entered with their letters in the expression - A for Raster A, B for Raster B, etc. All the functions available can be typed in the expression box or selected from the calculator buttons provided. The functions are not case sensitive.