Sara invested money at a bank that paid 3.5% annual interest compounded quarterly. If she had $4650 at the end of 4 yr what was her initial investment?

Answer 1

It's the same formula, but finding the answer backwards.

Amount=PR^n
P=principal,
R=interest rate per period
n=number of periods.

Here
A=$4650
n=4years*4 quarters per year
= 16 quarters
R=1+3.5%/4 quarters
=1.00875
So
4650=P*1.00875^16
P=4650/(1.00875^16)