Calculator question

[Thegoat]

I'm stuck on this part of a problem.

71.63660125 = 7.264891149*(a n¬6%) where 71.63660125 is the PV and 7.264891149 is the payment.

Solve for n:

I use the time value worksheet and type in 6% interest, the PV, payment, and ask the calculator to solve for n the answer it is giving me isn't correct.

My manual says that this can be solved with BA II Plus professional but I just can't figure it out. Anyone know a method to work out what n is?

[BeanCounter]

Where is the question? I don't know what's wrong.

[Harold Cherry]

Did you remember to enter the PV and the PMT with opposite signs, since these cash flows are opposite from each another? (You don't need the Professional model to solve for n; the regular BA II Plus is fine.) What answer does your manual give?

[Thegoat]

I get n = 7.97620188. My manual says n = 15.37019964. I am using BA II Plus Professional model calculator.

Maybe I should outline the problem. $100K loan scheduled for 30 annual payments. EAR = 6%. But at the 5th and 10th payments pay an additional $5K. Payments stay the same after the 10th payment.

PV after the 10th payment is 71,636.60125. Payment X is gathered from $100K = (X)a 30¬6% and then get X = 7,264.89115.

So to find the new n after t = 10, PV = (X)a n¬6%. So 71,636.60125 = (7264.89115)a n¬6%

So I put in 6% I/Y, 71,636.60125 PV, and 7264.89115 PMT into my calculator. Then compute n, and get n = 7.97620188.

[Thegoat]

I just noticed that if I put in the PV of 71,636.60125 into the FV instead then I get n = 16.37019964 which is exactly 1 over the supposed answer. Odd.