SOLUTION: how many years will it take for an amount of money to double when it is compounded annually by a 4.3% interest rate?

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Question 312241: how many years will it take for an amount of money to double when it is compounded annually by a 4.3% interest rate?
Found 2 solutions by nerdybill, mananth:
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
A = P(1 + r)^t
P = principal amount (the initial amount you borrow or deposit)
r = annual rate of interest (as a decimal)
t = number of years the amount is deposited or borrowed for.
A = amount of money accumulated after n years, including interest.
.
Let x = initial investment
then
A = 2x
Plug in what was given and solve for t:
+2x+=+x%281%2B.043%29%5Et+
Dividing both sides by x:
+2+=+%281.043%29%5Et+
+log%281.043%2C2%29+=+t+
+log%282%29%2Flog%281.043%29+=+t+
+16.5+=+t+ (years)


Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
let us assume the invested amount = 100
The money at the end of 1 year = 200
rate of interest = 4.3 %
compounded annually.
.
Formula
A= p(1+r/t)^nt
200=100(1+.043)^n
2=1.043^n
log2/log1.043= n
number of years = 16.46 for the money to double