The referred lessons are the part of this online textbook under the topic "Logarithms".
Save the link to this online textbook together with its description
Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson
to your archive and use it when it is needed.
Happy learning (!)
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The answer by @ewatrrr is different from my, since she makes intermediate rounding on the way;
I do not make intermediate rounding --- I round at the end, only, according to commonly accepted rules.
So, in sake of your safety, you better IGNORE her post.
Hi
In General
A = Accumulated Amount
P= principal = 4000
r= annual rate = .02
n= periods per year = 12
t= years = 10
Wish You the Best in your Studies.