For the record, I don't think you entered that equation correctly (assuming "over" indicates division), given that it is a decreasing value over time... but here it is:

The tiny hiccup that students catch in these kinds of problems is to remember to convert to the units of *t. * Here *t* is in months, and you have a 1-year period of time, or *t* = 12 months. Plug *t=12* into the equation:

P = 1500 / (1+8e^{-0.15(12)}) = 1500 / (1 + 8e^{-1.8}) = 1500 / (1+1.322) = 645.88

In the event the equation is supposed to look differently, please post the correction, and we can look again.