600 men can make a road in 500 days.
=> Total work = 600 x 500 = 3,00,000 units
Now, 600 men start working but after every hundred days, 50 men leave the work.
=> Work done in first 100 days = 600 x 100 = 60,000 units and total work done = 60,000 units
=> Work done in next 100 days = 550 x 100 = 55,000 units and total work done = 1,15,000 units
=> Work done in next 100 days = 500 x 100 = 50,000 units and total work done = 1,65,000 units
=> Work done in next 100 days = 450 x 100 = 45,000 units and total work done = 2,10,000 units
=> Work done in next 100 days = 400 x 100 = 40,000 units and total work done = 2,50,000 units
=> Work done in next 100 days = 350 x 100 = 35,000 units and total work done = 2,85,000 units
=> Work done in next 50 days = 300 x 50 = 15,000 units and total work done = 3,00,000 units
Therefore, total time (days) taken to make the road = 650 days
