Please solve Question 21 (a, b)

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21. If a hospital received $12,000 in payments per year at the end of each year for the next 12 years from an uninsured patient who underwent an expensive operation, what would be the current value of these collection payments: a. At a 4 percent rate of return? b. At an 8 percent rate of return? If the funds were received at the beginning of the year, what would be the current value of these collection payments for each of the two rates of return