A housing society wants to commission a swimming pool for its residents. For this, they have to purchase a square piece of land and dig this to such a depth that its capacity is 250 cubic metres. Cost of land is ₹500 per square metre. The cost of digging increases with the depth and cost for the whole pool is ₹4000 (depth)².

Use second derivative test to find the value of h for which cost of constructing the pool is minimum. What is the minimum cost of construction of the pool?