To know the cost of levelling you must know what is the total area of the plot land.
Plot land is in the form of a parallelogram and area of the parallelogram is given by = length of a parallel side × height between these parallel sides.
A = bh
So area = b h = 140 × 85 = 11900 sq m.
Cost of levelling:
For 1 sq. m cost is Rs 8.50
For 11900 sq. m cost = 8.50 × 11900
= Rs.101150