GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 08 Dec 2019, 13:28

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

If x and y are positive integers, is x/y a terminating decimal?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 59590
If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 30 Jan 2018, 07:19
1
13
00:00
A
B
C
D
E

Difficulty:

  95% (hard)

Question Stats:

38% (02:00) correct 62% (01:50) wrong based on 191 sessions

HideShow timer Statistics

Most Helpful Expert Reply
Math Expert
avatar
V
Joined: 02 Aug 2009
Posts: 8290
Re: If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 30 Jan 2018, 09:24
7
3
Bunuel wrote:
If x and y are positive integers, is x/y a terminating decimal?

(1) y/x is even
(2) The greatest common factor of x and y is 1



For \(x/y\) to be a terminating decimal, y should be multiple of 2 or 5 only..

Let's see the statements..

1) y/x is even...
Just confirms that y is MULTIPLE of 2 and also of y..
But y can be 2, x/y will be terminating decimal
If y is 18 and X is 3, x/y will be 1/6, a non terminating decimal.
Insufficient

2) GCF of x and y is 1.
x as 3 and y as 2 will give x/y is terminating decimal.
x as 3 and y as 7 will give x/y as non-terminating decimal.
Insufficient

Combined
X and y are co-prime and y/x as even means x is 1 and y is MULTIPLE of 2..
If x is 1 and y is 10, x/y is terminating..
If x is 1 and y is 30, x/y is not terminating..
Insufficient

E
_________________
General Discussion
Manager
Manager
avatar
B
Joined: 18 Jan 2018
Posts: 50
Re: If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 05 Feb 2018, 12:53
Bunuel wrote:
If x and y are positive integers, is x/y a terminating decimal?

(1) y/x is even
(2) The greatest common factor of x and y is 1


Statement 1, y/x is even i.e 2 * (num), therefore x/y = 1/ (2*num). If this num is 5, x/y is terminating, if num is 7 x/y is not terminating. Not sufficient.

Statement 2, since GCF of x & y is 1, values of x & y could be 10 & 5 or 10 & 7. This statement is not sufficient since the x/y could be terminating or not terminating.

Together, the statements would not confirm whether the value of y is 5 or 7 or anything else.

Hence the answer is E. Correct me if I am wrong.
Director
Director
avatar
P
Joined: 31 Jul 2017
Posts: 508
Location: Malaysia
Schools: INSEAD Jan '19
GMAT 1: 700 Q50 V33
GPA: 3.95
WE: Consulting (Energy and Utilities)
If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 25 Feb 2018, 05:06
Bunuel wrote:
If x and y are positive integers, is x/y a terminating decimal?

(1) y/x is even
(2) The greatest common factor of x and y is 1


We can do it by taking \(x = 1, y =6\) and \(x = 1, y = 4.\) It will stand for both the equations.
Hence, E
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 59590
Re: If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 24 Dec 2018, 02:46
Manager
Manager
avatar
G
Joined: 24 Dec 2018
Posts: 107
Concentration: Entrepreneurship, Finance
GMAT 1: 710 Q47 V40
Reviews Badge
Re: If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 02 Jan 2019, 05:41
x/y will be a terminating decimal only if y is 1 or a multiple of 2 and/or 5. y cannot be a multiple of any other number other than 2 and/or 5.

With this principle in mind, let's look at the statements

Statement 1: y/x is even. So, this means either x=1 and y=even number or x is a factor of y such that the resulting fraction y/x is even
Let's take examples to understand this.

If x=3 and y=6, then y/x=6/3=2(=even number). But since y=6, x/y can't be terminating decimal

If x=5 and y=10, then y/x=10/5=2(=even number). Since y=10, x/y is a terminating decimal

Thus, this statement is insufficient

Statement 2: If the greatest common factor between two numbers is 1, this proves that any of the following cases can be true: 1) the two numbers are odd and even or 2) the two numbers are prime number or 3) that at least one of the two numbers is 1.

In any of the above cases, we cannot distinguish which one will y be, hence we cannot be sure if x/y will be terminating or not.

Thus, this statement is insufficient

Combining statements 1 & 2: we get that contrary to what we had deduced in statement 1, x cannot be a factor of y. Thus, x=1 and y is an even number.

Checking on the three cases:

1) x=1 and y= even doesn't prove whether x/y will necessarily be terminating. Eg: x=1 and y=10: results in x/y terminating vs x=1 and y=14, results in x/y non-terminating
Although this is enough to prove that statement 2 is insufficient, let's check the other two cases as well for our understanding.

2) This cannot hold true since x=1 which is neither prime nor composite

3) This is a repeat of case 1.

Thus, the statements when combined are also insufficient

Answer is E
Senior Manager
Senior Manager
avatar
G
Joined: 23 Nov 2016
Posts: 312
GMAT 1: 690 Q50 V33
GMAT ToolKit User Reviews Badge
Re: If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 28 Mar 2019, 04:15
Bunuel wrote:
If x and y are positive integers, is x/y a terminating decimal?

(1) y/x is even
(2) The greatest common factor of x and y is 1


x/y will be terminating if y is in the form of 2^a * 5^b
now s1: y= 2*p*x
Now whether x/y will be terminating depends upon P. So not sufficient.
S2: Clearly not sufficient

S1+S2 x=1 but the rest depends upon P. So E
Director
Director
avatar
P
Joined: 24 Nov 2016
Posts: 927
Location: United States
Re: If x and y are positive integers, is x/y a terminating decimal?  [#permalink]

Show Tags

New post 17 Oct 2019, 05:10
Bunuel wrote:
If x and y are positive integers, is x/y a terminating decimal?

(1) y/x is even
(2) The greatest common factor of x and y is 1


Terminating decimal: one in which the denominator is made of only 2s, 5s or both (ie. 1/2 1/5 1/10);

Divisibility O & E:
E/E = (E,O,Fraction)
O/O = (O,Fraction)
E/O = (E,Fraction)
O/E = (Div by 0 [NA],Fraction)

(1) y/x is even: insufic.

y/x=even… E/E or E/O;
y/x=12/3=4; y/x=3/12=1/4; answer yes.
y/x=12/2=6; y/x=2/12=1/6; answer no.
y/x=12/1=12; y/x=1/12; answer no.

(2) The greatest common factor of x and y is 1: insufic.

x,y=co-prime
x/y=1/2; answer yes.
x/y=3/7; answer no.

(1&2): insufic.

x,y=co-prime, and y/x=EVEN then y/x≠E/E=E/O;
so if y=EVEN then x=ODD=1
y/x=10/1=10; y/x=1/10; answer yes
y/x=12/1=12; y/x=1/12; answer no

Answer (E)
GMAT Club Bot
Re: If x and y are positive integers, is x/y a terminating decimal?   [#permalink] 17 Oct 2019, 05:10
Display posts from previous: Sort by

If x and y are positive integers, is x/y a terminating decimal?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne