Question

@zepdrix Please help me! How long does it take $1075 to double if it is invested at 4% interest compounded quarterly?

a. 19.7 years
b.19.7 months
c. 17.4 years
d. none of these

Answer 1

\[\Large\bf\sf A\quad=\quad P\left(1+\frac{r}{n}\right)^{nt}\]

Answer 2

\[\Large\bf\sf r=0.04\]\[\Large\bf\sf n=4\]Quarterly means 4 times per year.
\[\Large\bf\sf P=1075\]

Answer 3

How long does it take to double.
So in other words, when does A = twice P.\[\Large\bf\sf 2150\quad=\quad 1075\left(1+\frac{0.04}{4}\right)^{4t}\]

Answer 4

Do you understand the setup?

Answer 5

Btw, cats rule -_-
dogs drool.
end of story.

Answer 6

Totaaly get it! =) Thanks!

Answer 7

Understand how to solve for t?
Gotta use logs and stuff :o

Answer 8

Or you could plug in your multiple choice options I suppose :3

Answer 9

I got it! Thank you so much! I think the answer is 17.3!

Answer 10

I mean 17.4 thanks for everything!