In what proportion should fine Darjeeling tea costing ₹2500 per kg be mixed with coarse tea costing ₹500 per kg, so that the cost of the mixture becomes ₹1000 per kg?

In what ratio must water be mixed with milk costing ₹12 per liter to obtain a mixture worth ₹8 per liter?

Wheat costing Rs. 80 per kg and Rs. 50 per kg are mixed with a third variety of wheat in the ratio 1 : 2 : 3. If the mixture is worth Rs. 75 per kg, then what will be the price of the third variety of wheat per kg?