Need some help please

Thanks CPhill. I understand now.

They are equivalent.

$$\frac{A-P}{P} = \frac{A}{P} - \frac{P}{P} = \frac{A}{P} - 1$$

By the way, these answers are not only equivalent to each other, but also right answers to the question asked.

Thanks. I'm still trying to figure how you did that though...

Let's approach it from the other direction

i = A/P   - 1           notice that  "1" can be written as P/P

So we have

i = A/P  - P/P         and since we have a common denominator, we can just write this all over that denominator...so we have....

i =  [ A - P ] / P        which is exactly the same as the other expression