Data Sufficiency

If x is integer, whether 30 is a factor of x ?

1. 30 is a factor of square of x.
2. 30 is a factor of 2x.

Answer should be (C).

1. If a number is factor of square of other number then same number will also be factor of other number.

In simple words, if A is factor of square of B then A is also factor of B.

ex. B = 60
square of B = 3600
A = 30

So 30 is factor of both 60 and 3600.

2. If a number is factor of twice of other number then same number will also be factor of other number.

In simple words, if A is factor of twice of B then A is also factor of B.

ex. B = 60
twice of B = 120
A = 30

So 30 is factor of both 60 and 120.

Hence choose (C)

crackthegmat2011 wrote:If x is integer, whether 30 is a factor of x ?

1. 30 is a factor of square of x.
2. 30 is a factor of 2x.

30 = 2 * 3 * 5 Rephrase The question Whether 2,3 and 5 all factors of x.


1. 30 is a factor of square of x.
For the square of a Number to have 30 as a factor, It must have at least one 2 , 3 and 5 in it,

So sufficient.

2. 30 is a factor of 2x

As 30 is a factor of 2x, We are are sure about 3 and 5 But May not about 2, So 2 can be factor of x or not be a factor of x.

So insufficient.

Answer should BE A

goyalsau wrote:
2. 30 is a factor of 2x

As 2x is a factor of 30,

Check the words...

30 is factor of 2x. Not 2x is factor of 30. So 2nd statement is also sufficient.

pm.mba11 wrote:

goyalsau wrote:
2. 30 is a factor of 2x

As 2x is a factor of 30,

Check the words...

30 is factor of 2x. Not 2x is factor of 30. So 2nd statement is also sufficient.

Thanks for checking But I still think answer should be A,

pm.mba11 wrote:

goyalsau wrote:
2. 30 is a factor of 2x

As 2x is a factor of 30,

Check the words...

30 is factor of 2x. Not 2x is factor of 30. So 2nd statement is also sufficient.

x can be 15, 30 is factor of 30 but 30 is not a factor of 15.
Statement B is not sufficient.

beat_gmat_09 wrote:

pm.mba11 wrote:

goyalsau wrote:
2. 30 is a factor of 2x

As 2x is a factor of 30,

Check the words...

30 is factor of 2x. Not 2x is factor of 30. So 2nd statement is also sufficient.

x can be 15, 30 is factor of 30 but 30 is not a factor of 15.
Statement B is not sufficient.

Hmm.. correct. Answer should be (A).

Sorry this way do you mean each individual will be sufficient, then it is not C?

pm.mba11 wrote:Answer should be (C).

1. If a number is factor of square of other number then same number will also be factor of other number.

In simple words, if A is factor of square of B then A is also factor of B.

ex. B = 60
square of B = 3600
A = 30

So 30 is factor of both 60 and 3600.

2. If a number is factor of twice of other number then same number will also be factor of other number.

In simple words, if A is factor of twice of B then A is also factor of B.

ex. B = 60
twice of B = 120
A = 30

So 30 is factor of both 60 and 120.

Hence choose (C)

crackthegmat2011 wrote:If x is integer, whether 30 is a factor of x ?

1. 30 is a factor of square of x.
2. 30 is a factor of 2x.

]

statement 1 is sufficient clearly
statement 2 is not sufficient; 2x:30 =x:15 so x could be 15,30, 45 blah blah blah
the answer should be A
whats the answer?