SOLUTION: Please Help with this one I have been trying to figure this out for a while. A business invests $10,000 in a savings account for two years. At the beginning of the second year

Question 149302: Please Help with this one I have been trying to figure this out for a while.
A business invests $10,000 in a savings account for two years. At the beginning of the second year, an additional $3500 is invested. At the end of the second year, the account balance is $15,569.75. What was the annual interest rate?

Answer by scott8148(6628) (Show Source): You can put this solution on YOUR website!
let r="annual interest rate"

after one year A=10000(1+r) __ A=10000+10000r

3500 is added __ after second year A=(13500+10000r)(1+r) __ 15569.75=13500+10000r+13500r+10000r^2

subtracting 15569.75 __ 10000r^2+23500r-2069.75=0

use the quadratic formula to find r __ r=(-23500�sqrt[23500^2-(4*10000*(-2069.75))])/[2*10000]

r=8.5%
RELATED QUESTIONS
I cannot figure this one out and I have been trying for a while now. I need help please.... (answered by Edwin McCravy)

Hey, I have been trying for a while now and I can't seem figure this one out. I would... (answered by stanbon)

1/(x-1)- 1/(x+2)= 1/2 I've been trying to figure this problem out for a while now. Help (answered by jcmtnez)

Can you please help me solve this? I have been trying to for a while now.... (answered by LinnW)

Write one thousand, five hundred six and three tenths as a decimal. I have been... (answered by checkley77)

Ok, I have been trying to solve this problem for a while. The problem is... (answered by jim_thompson5910,checkley71)

I have been trying to help my 8th grade daughter with her Algebra 1 homework. We have... (answered by ewatrrr)

I have looked for this problem on this site but did not see it anyplace. Please help.... (answered by solver91311)

Solve: 4^(1-x)=3*5^x I hope someone can help me, I have been trying to figure this one... (answered by stanbon,scott8148)