Here is the compound interest formula solved for years: <span>Years = {log(total) -log(Principal)} ÷ log(1 + rate) </span>Years = {log(800) - log(600)} <span>÷ log(1.025) </span><span>Years = {2.903089987 -2.7781512504} / 0.010723865392 </span>Years = {
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0.1249387366
} / </span></span></span><span><span><span>0.010723865392 </span>
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Years =
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11.6505319708
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That's how many years it takes for the $600 to become exactly $800.00 The question specifically asks how long for the money to be MORE than $800.00?
So, if we enter 800.01 into the equation, then the answer is Years = {log(800.01) - log(600)} <span>÷ log(1.025) </span><span>Years = {2.9030954156 -2.7781512504} / 0.010723865392 </span>Years =
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0.1249441652
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/ 0.010723865392 <span>
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Years = 11.6510381875
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The answer is 10 as the diameter because it says to estimate pi as 3. Since we know the circumference is 30 we can reverse it to find the diameter, since Circumference is pi time diameter.
