Practice test 2

Wow!

I am getting B).

Whats the oa Feruza?

cramya wrote:Wow!

I am getting B).

Whats the oa Feruza?

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Wprking sheet cramya p[lzzzz

Vishu

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

Wprking sheet cramya p[lzzzz

Similar to Ronnie's way!!!

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

OA is B

Thanks

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)