Monday, February 22, 2010

Interest Schemes

So a few weeks ago I gave you this offer:

The effective annual interest rate is 4%. You pay me $300 today and I will pay you $0.50 a day forever - you'll make your money back in two years!

I told you I wouldn't do it, but I was wrong. Way wrong in fact - were talking trillions in 20 years...


So... I've got a new scheme for you and I'm pretty sure I'm not wrong on this one. I'll leave this one open ended and you can leave your opinion in the form of a comment.

Yes or No? - You pay me $2,000 today, and I'll pay you $50 three times a year until you die. The interest rate is 2.45%. You expect to live at least 30 more years.

Hint: find the atomic number of nickle. At this number of years the two plans are equal (the interest rate was choosen for such an outcome).

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