Dumper arrives at a shovel at constant rate of 10 per hour. The service rate is constant at 15 per hour, At a time, the expected number of dumper in the que is

A. Working time B. Rest internal C. Night D. All

A. Rifle bullet test B. Gap test C. Ageing test D. Water resistance test

A. Striping B. Open cast C. Placer D. Long wall

A. 0.25 to 0.75 B. 3 to 4.5 C. 1.5 to 1.7 D. None