Question 616091
Find how long it takes for $1400 to double if it is invested at 3% interest compounded monthly.
using formula: A=P(1 + r/n)^(nt)
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P is 1400
A is 2800 (double P)
r is .03
n is 12 (times compounded per year)
t is what we're looking for
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plug it all in and solve for t:
{{{A=P(1 + r/n)^(nt)}}}
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{{{2800 = 1400(1 + .03/12)^(12t)}}}
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{{{2800 = 1400(1 + 0.0025)^(12t)}}}
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{{{2800 = 1400(1.0025)^(12t)}}}
.
{{{2 = (1.0025)^(12t)}}}
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{{{log(1.0025,2) = 12t}}}
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{{{log(2)/log(1.0025) = 12t}}}
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{{{log(2)/12log(1.0025) = t}}}
.
{{{23.13 = t}}} (years)