Continued from #2 Suppose Michael needed to save $250,000 in 15 years, and he was looking at various combinations in his investment plan, such as getting a higher interest rate r; increasing the amount of his monthly contributions; or increasing the number of years of investment.

Set up an Excel model, and then use Goal Seek to answer the following questions. (Use the original information given in #2, and for each question, only one parameter changes.) (a) What interest rate r would accumulate $250,000 in 15 years with the monthly contribution of $500? (b) Suppose Michael could not get a higher rate (that is, the interest rate remains 8.2%), and $500 was the maximum he could put aside each month. As a result, the only flexible parameter is the term t years. How many years would it take to accumulate $250,000?