Wow!
I am getting B).
Whats the oa Feruza?
Practice test 2
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Source: Beat The GMAT — Data Sufficiency |
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ronniecoleman
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IMO B
X = 8*Y + 12
1. X = 12U
12U-12 = 8Y
12( U-1) / 8 = Y
Plug in values...
Insuff
2.
X = 8*Y + 12
X= 8*12Z +12
12( 8Z+1)
Y = 12 Z
Z EVEN
hcf = 12
Z is ODD
hcf = 12
X = 8*Y + 12
1. X = 12U
12U-12 = 8Y
12( U-1) / 8 = Y
Plug in values...
Insuff
2.
X = 8*Y + 12
X= 8*12Z +12
12( 8Z+1)
Y = 12 Z
Z EVEN
hcf = 12
Z is ODD
hcf = 12
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cramya
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Similar to Ronnie's way!!!Wprking sheet cramya p[lzzzz
Explaining a little more:
z even(NOT 0 though since x and y are positive)
If z is even then 8z+1 will be odd so there will no common factor between z and 8z+1 other than 1 making the hcf 12
x = 12(8z+1)
Y = 12 Z
gcd/hcf = 12
z odd
If z is odd then still 8z+1 will be one more than the multiple of z therefore z and 8z+1 will have no common factor other than 1 making 12 the gcd/hcf
gcd/hcf = 12
SUFFICIENT
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cramya
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Received pm to explain more.
Stmt I
x=8y+12
x=12u
12u = 8y+12
12(u-1)/8 = y
3(u-1) / 2 = y
u-1 has to be even since 3/2 is not an integer i.e u->odd
Plug in u=3 x=36 y=3
hcf is 3
u=5 x=60 y=6
hcf = 6
INSUFF
Stmt II
x = 12(8z+1)
Y = 12 Z
z even(NOT 0 though since x and y are positive)
If z is even then 8z+1 will be odd so there will no common factor between z and 8z+1 other than 1 making the hcf 12
x = 12(8z+1)
Y = 12 Z
gcd/hcf = 12
z odd
If z is odd then still 8z+1 will be one more than the multiple of z therefore z and 8z+1 will have no common factor other than 1 making 12 the gcd/hcf
gcd/hcf = 12
SUFF
B)
Stmt I
x=8y+12
x=12u
12u = 8y+12
12(u-1)/8 = y
3(u-1) / 2 = y
u-1 has to be even since 3/2 is not an integer i.e u->odd
Plug in u=3 x=36 y=3
hcf is 3
u=5 x=60 y=6
hcf = 6
INSUFF
Stmt II
x = 12(8z+1)
Y = 12 Z
z even(NOT 0 though since x and y are positive)
If z is even then 8z+1 will be odd so there will no common factor between z and 8z+1 other than 1 making the hcf 12
x = 12(8z+1)
Y = 12 Z
gcd/hcf = 12
z odd
If z is odd then still 8z+1 will be one more than the multiple of z therefore z and 8z+1 will have no common factor other than 1 making 12 the gcd/hcf
gcd/hcf = 12
SUFF
B)
