Data Sufficiency

Methods or strategies

the statement i believe is saying that

z is directly proportional to x and y

therefore,

2+z = 2x
2+z = 3y

therfore, 2+z = 2x*3y

x/(x+y) =? when z=12

Statement (1)
z=6, x =5y
2+6 = 2*5y *3y
8 = 30 y
8/30=y
8/10 = y
2+6 = 3y
8/3 = y

when, z=12

12+2 = 2x * 8/3
14*3/16 = x
x= 21/8

we know x and y we can easily find the value of x/(x+y)

Statement (2)
z=0, x =y+1

2+0 = 2y+2*3y
2= 6y^2 + 6y
3y^2 + 3y -1 =0
3y^2 +3y = 1
3y (y+1) = 1
3y =1 or y+1 =1

y=1/3, y=0

the question says x and y are positive when z>0, here z=0, therefore we can discard the value for y=1/3
Insufficient.

Thus A. whats the OA.


I dont know if I have correctly interpreted the question. Pls do let me know if anybody thinks otherwise.

You are correct. Why are u so good at these questions.