Decimal Expression

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 113
Joined: Wed Dec 07, 2011 7:20 am
Thanked: 3 times

Decimal Expression

by manik11 » Fri Feb 26, 2016 7:33 am
If x and y are positive integers, does the decimal expression of X/Y have fewer than 5 distinct digits to the right of the decimal place?

(1) y is a prime digit.
(2) y is neither 3 nor 7.

OA : C

Hi Experts..Could you guys please show how statement 2 is insufficient?
Source: — Data Sufficiency |

User avatar
Legendary Member
Posts: 2663
Joined: Wed Jan 14, 2015 8:25 am
Location: Boston, MA
Thanked: 1153 times
Followed by:128 members
GMAT Score:770

by DavidG@VeritasPrep » Fri Feb 26, 2016 7:49 am
manik11 wrote:If x and y are positive integers, does the decimal expression of X/Y have fewer than 5 distinct digits to the right of the decimal place?

(1) y is a prime digit.
(2) y is neither 3 nor 7.

OA : C

Hi Experts..Could you guys please show how statement 2 is insufficient?
For statement 2, all we know is that we're dealing with positive integers and y is not 3 or 7.
Case 1: x = 1, y = 2. 1/2 = .5 The answer is YES we have fewer than 5 distinct integers to the right of the decimal.

Case 2: x = 1, y = 32 = .03125 Now the answer is NO, we don't have fewer than 5 distinct integers to the right of the decimal. (I'd be surprised if the GMAT actually asked us to work with such numbers, however.)

In any event, we can get a YES and a NO, so the statement is not sufficient.
Veritas Prep | GMAT Instructor

Veritas Prep Reviews
Save $100 off any live Veritas Prep GMAT Course

User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pm
Location: New York, NY
Thanked: 13060 times
Followed by:1906 members
GMAT Score:790

by GMATGuruNY » Fri Feb 26, 2016 7:50 am
manik11 wrote:Hi Experts..Could you guys please show how statement 2 is insufficient?
Case 1: x/y = 1/2 = 0.5.
Here, x/y has fewer than 5 distinct digits to the the right of the decimal.
Case 2: x/y = 1/13 = 0.07692....
Here, x/y does NOT have fewer than 5 distinct digits to the right of the decimal.
INSUFFICIENT.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3

GMAT Instructor
Posts: 2630
Joined: Wed Sep 12, 2012 3:32 pm
Location: East Bay all the way
Thanked: 625 times
Followed by:119 members
GMAT Score:780

by Matt@VeritasPrep » Fri Mar 04, 2016 4:26 pm
I typically just think of extreme numbers. Suppose x = 1 and y = 5. Then we have .2, so we have fewer than 5 digits. Now suppose x = 1 and y = 3747576777. Yuck! That will give us a lot of distinct digits, so we're set: S2 isn't sufficient.