Question

A 140 Motor Grader will be used to maintain a 1,700 ft haul road. It is estimated that this work will require 1 passes in second gear and 3 passes in third gear. Use an efficiency factor of 85%. Grader speeds are given in the chart below. The cost per hour for the grader with an operator is $178 per hour. How much time in minutes is required to perform this task? Round to the nearest whole minute.

Maximum Travel Speed (mph) 2.2 Forward Gear First Second3.0 Third Fourth6.0 4.3

Answer 1

Px D Time required to complete the task where P is the number of passes D is the dis tan ce travelled in each pass S is the grader speed E is the efficiency From the question Efficiency =85%-0.85 Haul distance = 1700ft= (1700 / 5280) mile travel speed (2nd gea)-3mph Number of passes 1 travel speed (3d gea)-4.3mph Number of passes 3 SxE 1x 1700/5280) mile 3x(1700/5280)mile (3mphx0.85) 4.3mphx0.85) Time taken - = 0.3905 hrs 4.3mphx 0.85 Time taken 0.3905h x 60min 23.43 min 24 min Cost per hou -$178: for 24 min =-x178 = $71.2~$72 Answer Time taken0.3905h x 60min 23.43 min24 min 24 60