Suppose that random access memory (RAM) can be added to your computer at a cost of $8 per gigabyte. Suppose also that the value to you, measured in terms of your willingness to pay, of an additional gigabyte of memory is $32 for the first gigabyte, and then falls by one-half for each additional gigabyte. Based on marginal costs and marginal benefits, how much gigabytes of memory should you purchase?