77) Consider the following operations : 1.Drilling 2.Blasting 3.Mucking 4.Placing steel 5.Placing concrete. The correct sequence of these operations in tunnel construction is

78) For a given activity, the optimistic time, pessimistic time and the most probable estimates are 5, 17 and 8 days respectively, The expected time is

79) The maximum rimpull in the first gear of a tractor while towing a load is 6300 kg. The tractor weighs 12.5 tonnes and is operating along a 2 percent upgrade and the rolling resistance is 45 kg/tonne. Pull available for towing the load is

80) Grader is used mainly for

81) Which one of the following is not an excavating and moving type of equipment