One-time price discount Inventory Model : Operations Management

Question:

You want to decide how much wheat flour to buy. Monthly demand for your family is 10kg, which is bought monthly. Maximum retail price (MRP) is INR 400, on which generally there is a discount of 20%. But due to a pandemic situation, you are expecting that the flour would be sold on MRP in the coming months. Today, 20% discounted wheat flour is available in the local grocery store. Based on the learning in your operations management course, suggest the right amount of wheat flour to be purchased this time. (Wheat flour should be used within 3 to 4 months of preparation)