Jack refused to buy a computer offered to him by Sam for $2048. A year later, Sam again offered Jack the same computer for $1280 but Jack refused again. The next year, he again offered Jack the same computer for $800. One year after that, the computer was again offered but Jack did not buy it. The following year, Jack bought the computer from Sam for $312.50. If the rate of discount offered every year were constant, at what price was the computer offered in the fourth year?