Newton currently has an account balance of $6,225.18. He opened the account 15 years ago with a deposit of $4,543.11. If the interest compounds daily, what is the interest rate on the account?

Question

anonymous · Answer

what is the compounding formula you are given?

anonymous · Answer

The formula would be 6225.18=4543.11(1+r/365)^(365*15) I think. I just don't know how to solve it.

anonymous · Answer

looks good  ...divide both sides by 4543.11 and exponentiate both sides  with (1/(365*15))

anonymous · Answer

I'm still confused. 1.37=(1+r/365)^5475 
What do I do from there?

anonymous · Answer

$$1.37^{1/5475}=((1+r/365)^{5475})^{1/5475}$$

anonymous · Answer

you good on this?

anonymous · Answer

Not really.

anonymous · Answer

what part?

anonymous · Answer

All of it. I can normally figure out problems like this, but when it comes to finding the rate in problems like this, I get stumped.

anonymous · Answer

I understand the beginning of the problem, but when you put the most recent equation, I got even more confused.

anonymous · Answer

$$(C ^{a})^{b} =C ^{ab}  $$

anonymous · Answer

exponentiating both sides with (1/5475) gets rid of the exponent on the right side because 5475*(1/5475) =1

anonymous · Answer

So it would just be 1.37^5475=1+r/365 ?

anonymous · Answer

1.37^(1/5475) =1+r/365

anonymous · Answer

Ohh. Okay. 
So is the answer 364.02 ?

anonymous · Answer

no

anonymous · Answer

Omg. 
I got 1.00006=1+r/365
Then I multiplied 1.00006 by 365 and got 365.02 then subtracted 1 from both sides and got 364.02.

anonymous · Answer

hit these keys:
5
4
7
5 
$$\frac{ 1 }{ x }$$
memory store
1.37
$$y ^{x}$$
memory recall
-
1
*
365

anonymous · Answer

So 2.1% ?

anonymous · Answer

yep:)

anonymous · Answer

Yay. (: Finally.