Within a rectangular courtyard of length 60 feet, a graveled path, 3 feet wide, is laid down along all the four sides. The cost of graveling the path is Rs 2 per sqft. If the path had been twice as wide, the gravek would have cost Rs 984 more. The width of the courtyard is : (Please explain also! I'm making some mistake at one of the steps..)

1) 24
2) 40
3) 45
4) 54