how to figure interest rate with time rate added?

Answer 1

I'm not sure what you're asking for exactly but I take this to mean how to find the interest rate when the time and compounding period are givens (along with the principal and the final amount). This will solve for i, the interest rate.

X = P(1+i/n)^(nt)
X/P = (1+i/n)^(nt)
ln (X/P) = ln (1+i/n)^(nt) = nt * ln (1+i/n)
[ln (X/P) / nt] = ln(1+i/n)
e^[ln (X/P) / nt] = e^[ln(1+i/n)] = 1+i/n
e^[ln (X/P) / nt] - 1 = i/n
n(e^[ln (X/P) / nt] - 1) = i

Answer 2

A = P(1 + r/n)^nt

A = amount after
P = amount prior
r = rate (in decimal percentages)
n = Frequency (12 = monthly, 4 = quarterly, 365 = daily)
t = time (in years)


A = Pe^rt

is the same, but it is compounded continuously. e is ~2.7

Answer 3

That's a very brief question. I don't know what you mean though. Please elaborate.