What are the Formulas for Simple and Compound intrest??

[Nolan92]

All I want is the formulas thanks since I forgot most of them and have already come up with some word questions.

simple

Solving for the Final amount (one example)
Solving for the Principal amount (one example)
Solving for the time (one example)
Solving for the interest rate (one example)

I have the word-problems just need the formulas I know the basic formula for simple is P=rt

compound

Here is where I'm totally clueless

Solving for the Final amount (one example)
Solving for the Principal amount (one example)

 

[Joel`]

Compound interest:

F=P(1+i)^n

where F is the final amount, P is the principal, i is the interest rate and n is the number of periods (usually years).

It's basic algebra to find P. You're gonna need to use logarithms to re-arrange for n. To find i, do the nth root of F/P and -1.

To find n, choose any base log you like. In natural logs:

n=(lnF-lnP)/ln(1+i).