Invest Problem. Pls Help?

A guys has a 0,000 and he wants to invest this for 3 years to get a maximum earning per $ he invest.
He has the option of investing his money in two plans. Plan A guarantees that each dollar invested will earn 70 cents a year, hence, and plan B guarantees that each peso invested will earn .00 two years hence. In plan B, only investments for periods that are multiple of 2 years are allowed.
I just need the working equation for this.. please help me. im just a beginner.

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August 29th, 2010 at 5:02 pm
Plan A would end up with $100,000 * 1.7 * 1.7 * 1.7, or $491,300. A fantastic (unbelievable) return.
Plan B would end up with $100,000 * 12 (pesos/dollar) * $2 + $100,000 = $2,500,000 in 2 years. heck, who needs the 3rd year!