I thought about this solution. However, the statement confused me with the 1 / k - 1 fraction. Thanks a lot!

A little help please

If k ≠ 0, 1 or -1, is 1 / k > 0?

1) 1 / k - 1 > 0

2) 1 / k + 1 > 0

OA: A

I have a doubt on this one. Any help, please?

What is the value of x + y?

1) 12x - 3y = 15

2) y = 4x - 5

OA: E

I can work though the statements. However, why can't I treat 1 and 2 together as a system of equations?

Need help with this one please

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

OA: B

Can't find the correct solution for this one. Any help?

The price of a left-handed widget increased 20% in 1981 and 10% in 1982. By approximately what percent would the price at the end of 1982 have to be decreased to restore the price of the widget to its pre-1981 price?

A) 40%
B) 35%
C) 30%
D) 26%
E) 24%

OA: E

One last help with proportions please

Running at their respective constant rates, machine X takes 2 days longer to produce w widgets than machine Y. At these rates, if the two machines together produce 5w/4 widgets in 3 days, how many days would it take machine X alone to produce 2w widgets?

A) 4
B) 6
C) 8
D) 10
E) 12

OA: E

Need help with this one

Machine X and machine Y, working at the same time, produce w widgets in k hours. Machines A, B and C, together produce w widgets in k - 2 hours. If all the machines have the same productivity, what is the value of K?

A) 2
B) 3
C) 6
D) 8
E) 9

OA: C