Question

Ceasar opens a bank account and makes an initial deposit of $800. The banker tells Ceasar that he is going to receive an annual rate of 10% on his investment. Find the bank balance assuming Tom leaves the account untouched for 8 years.

Answer 1

As it was not mentioned, we assume that it is a simple interest rate (it would be different if it was compound interest rate)
 

So we have now:
- initial deposit of $800  (p=800)
- annual rate of 10%      (r=0.1)
- leaves the account untouched for 8 years  (t=8)

Apply the formula in the chart attached:

$I=p*r*t=800*0.1*8=640~$

So the interest is 640$

Add this to the original deposit (800$) to get the full amount of money (the balance) after 8 years

800+640=1440$


Done!!

I hope that helps!

Answer 2

800(1+.10)^8
$1,714.87