# interest math

posted by .

doris browning deposited \$8000 into a savings account paying 5.25% interest. how long will it take for her investment to grow to \$10,100. The answer i got was 4yr 11mo 30 days but that is wrong someone please help

• interest math -

I am assuming you are using the standard compound interest method, simple interest is seldom used for periods longer than a year

8000(1.0525)^n = 10100
1.0525^n = 1.2625

n log 1.0525 = log 1.2625
n = 4.5554 years , assuming the rate is 5.25 per annum compounded annually

at continuous compounding

8000 e^(.0525n) = 10100
e^(.0525n) = 1.2625
take ln of both sides
.0525n = ln 1.2625
n = 4.4399 years

btw:
at simple interest
8000 + 8000(.0525)n = 10100
n = 5 years

none of the 3 ways I used produces your answer, I have no idea how you got that.

• interest math -

I belive its 5 years.( asuming the interest rate is anual)

8000x .0525 = 420
(Check[8000/420*5=100])
so 10100-8000 = 2100
Finally 2100/420 = 5

Hope that's right.

## Respond to this Question

 First Name School Subject Your Answer

## Similar Questions

1. ### Math

If you deposit P dollars into a bank account paying an annual interest rate r, with n interest payments each year, the amount A you would have after t years is A=P(1+r/n)^nt. Kevin places \$100 in a savings account earning 6% annual …
2. ### math

Alicia Eastman deposited \$2,000 in a savings account at the Biltmore Bank paying 6% ordinary interest. How many years will it take for her investment to amount to \$2,600?
3. ### math

Alicia Eastman deposited \$2,000 in a savings account at the Biltmore Bank paying 6% ordinary interest. How many years will it take for her investment to amount to \$2,600?
4. ### math

Alicia Eastman deposited \$2,000 in a savings account at the Biltmore Bank paying 6% ordinary interest. How many years will it take for her investment to amount to \$2,600?
5. ### math

Alicia Eastman deposited \$2,000 in a savings account at the Biltmore Bank paying 6% ordinary interest. How many years will it take for her investment to amount to \$2,600?
6. ### Pre-Algebra can you please help?!

Lester deposited \$400 into a savings account earning 4.5% simple interest, and \$450 into an investment account earning 3.2% interest compounded annually. What was the total interest he earned in 3 years?
7. ### Can you help me with this math problem? ASAP plz!

Lester deposited \$400 into a savings account earning 4.5% simple interest, and \$450 into an investment account earning 3.2% interest compounded annually. What was the total interest he earned in 3 years?
8. ### Lat math question for some days. Can y'all help?

Huan deposited \$850 into a college savings account earning 4.8% interest compounded annually. He also deposited \$850 into a second account earning 4.8% simple interest. He made no additional deposits. After 10 years, which account …
9. ### Mathematics of INVESTMENT

Q: Ms. Parker deposits \$8000 in one simple interest account and \$2000 in a second simple interest account. The interest rate on the \$8000 account is 2% more than the rate on the \$2000 account. If the total yearly amount of interest …
10. ### Algebra

Chloe wants to invest a total of \$39000 into 2 savings account, one paying 6% per year in interest and the other paying 9% per year in interest (a more risky investment). If after 1 year she wants the total interest from both accounts …

More Similar Questions