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now representing them. Substituting the average values from the note sheet on Fig. 2 (page 151), our formula becomes:

 

B=(p+[a+0.18+0.17+0.16+distance hauled100(0.22+0.26)]27L) 1.27,

or

B(p+[a+0.51+(0.0048)distance hauled]27L)1.27

(2)

Formula 2 is applicable to any kind of earth hauled by men working at the speeds recorded on the note sheet to any distance.

For sand, still using the values given on the note sheet (Fig. 2):

B=(0+[ 1.24+0.51+0.0048(distance hauled)]272.32)1.2,

or

B=25.86+0.071(distance hauled)

(3)

For a 50-foot haul:

B=25.86+0.071(50)=29.4 min. as the time for one man and wheel one cubic yard of sand a distance of 50 feet.

In classes of work where the percentage of rest varies with the different elements of an operation it is most convenient to correct all of the elementary times by the proper percentages before combining them. Sometimes after having constructed a general formula, it may be solved by setting down the substitute numerical values in a vertical column for direct addition.