Inside a rectangular park of dimensions 100m × 80m, walking paths 3m wide are to be constructed as shown in the figure given below (a 3m-wide border path runs around all four sides of the park, plus one 3m-wide path down the vertical centre and one 3m-wide path across the horizontal centre, dividing the interior lawn into four equal rectangular plots). Find the cost of construction of paths at the rate of ₹ 120/m².