steven7dong wrote:The annual rent collected by a corporation from a certain building was x percent more in 1998 than in 1997 and y percent less in 1999 than in 1998. Was the annual rent collected by the corporation from the building more in 1999 than in 1997?
(1) x > y
(2) xy/100 < x-y

I saw that lots of post states that the 1999 rent collection is R(1+x/100)(1-y/100), however, I have problem understanding this, because I think the 1999 rent collection is R(1+x/100)(1+y/100).
According to the correct answer, looks like the equation they used is (1998 rent-1999 rent)/1998 rent. That's how they got R(1+x/100)(1-y/100)
The equation I used is (1999 rent-1998 rent)/1998 rent and that is how I got R(1+x/100)(1+y/100).
How do we determine which one minus which when doing this kind of questions.

Thanks for your time XP

The annual rent collected by a corporation from a certain building was x percent more in 1998 than in 1997 and y percent less in 1999 than in 1998. Was the annual rent collected by the corporation from the building more in 1999 than in 1997?

(1) x > y
(2) xy/100 < x - y

b