Page:Shop management.djvu/166

159 necessary delay, are recorded and the percentages of rest are calculated.

Formulæ are convenient for combining the elements. For simplicity, in the example of barrow excavation, each of the unit times may be designated by the same letters used on the note sheet (Fig. 2) although in practise each element can best be designated by the initial letters of the words describing it.

Let

Then

''B=(p+[a+b+d+f+(c+e)] )(1+P) ... (1) ''

This general formula for barrow work can be simplified by choosing average values for the constants, and substituting numerals for the letters