Based on some data, a business analyst concluded that the basic average service life of a certain type of machine is 2.5 years. He also discovered that the machine lifetime increases with the quality of the machine, which will be reflected by its price. On average, the life will increase (beyond 2.5 years) for 6 months for every 1000 SGD worth of the machine price. Suppose the machine from manufacturer ABC costs 10,000 SGD and the price remains constant in the future, how many machines will the company need to purchase from ABC in order to fully cover the operation in the next 10 years?