Calvin Jacobs is a widower who recently retired after a long career with a major Midwestern manufacturer. Beginning as a skilled craftsman, he worked his way up to the level of shop supervisor over a period of more than 10 years with the firm. Calvin receives Social Security benefits and a generous company pension. Together, these amount to over $4,500 per month (part of which is tax free). The Jacobses had no children, so he lives alone. Calvin owns a 2 bedroom rental house that is next to his home, and the rental income from it covers the mortgage payments for both the rental house and his house. Over the years, Calvin and his late wife, Allie, always tried to put a little money aside each month. The results have been nothing short of phenomenal. The value of Calvin's liquid investments (all held in bank CDs and savings accounts) runs well into 6 figures. Up to now, Calvin has just let his money grow and has not used any of his savings to supplement his Social Security pension, and rental income. But things are about to change. Calvin has decided to travel and start reaping the benefits of his labors. He has therefore decided to move $100,000 from a savings account to 1 or 2 high-yielding mutual funds. He would like to receive $1,000 to $1,500 a month from the fund(s) for as long as possible because he plans to be around for a long time.

Assume Calvin invests in a mutual fund that earns about 10% annually from dividend income and capital gains. Given that Calvin wants to receive $1,000 to $1,500 a month from his mutual fund, what would be the size of his investment account 5 years from now? How large would the account be if the fund earned 15% on average and everything else remained the same? How important is the fund's rate of return to Calvin's investment situation?