Hi,
Firstly, I have done a search and I couldn't find this question. (I searched for both "xy+z" and "x(y+z)" )
Secondly, I apologise if it is a silly question BUT ...
I ended up getting each of the options other than d as a “must be true”, so obviously I have missed out something basic in my Quant studies. Can someone please tell me what’s wrong with my calculations?
The question is:
If xy + z = x(y+z), which must be true?---
1) x=0 and z=0
substituting the values of x and z in the stem’s equation,
0*y + 0 = 0( y + 0)
and so 0=0 ….. True
2) x=1 and y = 1
substituting the values of x and y in the equation, we get
1*1 +z =1(1+z) and from there,
1+z =1+z …. True
3)y=1 and z =0
substituting the values of y and z in the equation, we get
x*1 +0 =x(1+0)
and so x = x….. True
4)x=0 or y=0
substituting the value of x, we get
0*y +z= 0(y+z)
and so, z=0, which may or may not be true…… so discarded.
5)x=1 or z=0 (official answer)
Thanks.
Shilo
Firstly, I have done a search and I couldn't find this question. (I searched for both "xy+z" and "x(y+z)" )
Secondly, I apologise if it is a silly question BUT ...
I ended up getting each of the options other than d as a “must be true”, so obviously I have missed out something basic in my Quant studies. Can someone please tell me what’s wrong with my calculations?
The question is:
If xy + z = x(y+z), which must be true?---
1) x=0 and z=0
substituting the values of x and z in the stem’s equation,
0*y + 0 = 0( y + 0)
and so 0=0 ….. True
2) x=1 and y = 1
substituting the values of x and y in the equation, we get
1*1 +z =1(1+z) and from there,
1+z =1+z …. True
3)y=1 and z =0
substituting the values of y and z in the equation, we get
x*1 +0 =x(1+0)
and so x = x….. True
4)x=0 or y=0
substituting the value of x, we get
0*y +z= 0(y+z)
and so, z=0, which may or may not be true…… so discarded.
5)x=1 or z=0 (official answer)
Thanks.
Shilo
