If Sandy spent Rs. 400 on fencing and Rs. 500 on ploughing the land he had earlier (ABCD), find the cost of fencing per unit and cost of ploughing per square unit respectively.
Perimeter of ABCD = 2 (x + y) units
So, cost of fencing per unit = Rs.4002(x+y)=Rs.200(x+y)
Area of ABCD = xy square units
Cost of ploughing per unit = Rs.500(xy)