Annuties

[JAnderson]

Hello there I'm a little stuck on this problem in which I know what formula to use and yet I keep getting a wrong answer.

The question reads:
If you make monthly deposits of $544.00 into an ordinary annuity earning 5.51% compounded monthly, how many deposits must you make so that you will have at least $162,000.00? Note: your answer should be an integer

I know to use the future value of an annuity formula which for us is S=R[((1+r/m)^mt-1)/(r/m)]
R being periodic payments
r being annual rate of interest
m being number of times per year interest is being compounded
t being the number of years the amount is deposited or borrowed


So what I did was plug in the values which I took from the question in where:
R=544.00
r=0.0551
m=12
t= unknown to solve for.

However any time I use these numbers and try to solve for t, I've gotten a wrong answer. Am I confusing something here for something else?

 

[GeneralSynopsis]

1. Check your formula (it looks OK to me but ASCII maths can be ambiguous, and you are looking for a number of months not years)
2. Note it asks for the number of months/periods to have at least \(\$162,000.00\). This means find the integer number of months \(n\) so that \(P(n)\) the future value of the annuity satisfies \(P(n-1)<162,000.00\) and \(P(n)\ge 162,000.00\)