Question 9 (nov.17th)

[bacali]

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) 100xy < x – y

OA: B

[lachlanc]

Are you sure statement II is copied correctly? I think the question would make more sense if it was xy/100 < x - y

[rtfact]

Statement 1 does not help much. Suppose there was an increase by 1/2 and then a decrease by a 1/3 -> the rent would not change. So if the increase would have been a bit smaller - 1/3-0.0001 then the rent in 99 would be higher than in 97, and if the increase would have been a bit higher- 1/3+0.0001 then the rent in 99 would be lower than in 97.

we have to determine whether
r<r(100+x)(100-y)/100*100=r(1+(x-y)100-xy/100*100)
or
0<(x-y)100-xy/100*100

while remembering that x,y>0
from statement 2 we can conclude that 0<xy-xy/100*100 is true. hence B.

[4meonly]

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) 100xy < x – y

Can anybody confirm that statement 2 is correct?
Otherwise I do not understand rtfact's solution

Statement 1 does not help much. Suppose there was an increase by 1/2 and then a decrease by a 1/3 -> the rent would not change. So if the increase would have been a bit smaller - 1/3-0.0001 then the rent in 99 would be higher than in 97, and if the increase would have been a bit higher- 1/3+0.0001 then the rent in 99 would be lower than in 97.
we have to determine whether
r<r(100+x)(100-y)/100*100=r(1????+(x-y)100-xy/100*100)
or
0<(x-y)100-xy/100*100
while remembering that x,y>0
from statement 2 we can conclude that 0<xy-xy/100*100 is true. hence B.

[xyzabc123]

I think (2) should be xy < 100(x-y)