In the decimal representation of x, where 0 < x < 1, is the tenths digit if x nonzero?
(1) 16x is an integer.
(2) 8x is an integer.
am totally stumped...
Integer Bouncer
This topic has expert replies
-
- Master | Next Rank: 500 Posts
- Posts: 167
- Joined: Wed Jun 11, 2008 10:58 pm
- Thanked: 2 times
- Followed by:1 members
- VP_Tatiana
- GMAT Instructor
- Posts: 189
- Joined: Thu May 01, 2008 10:55 pm
- Location: Seattle, WA
- Thanked: 25 times
- Followed by:1 members
- GMAT Score:750+
You guys are right; the digit after the decimal point is the tens digit, not the units digit. My bad and thanks for the correction!
Last edited by VP_Tatiana on Sun Jul 20, 2008 2:05 pm, edited 1 time in total.
Tatiana Becker | GMAT Instructor | Veritas Prep
-
- Master | Next Rank: 500 Posts
- Posts: 320
- Joined: Sun Jan 13, 2008 10:00 pm
- Thanked: 10 times
The answer is B. 8x will always yield a non zero tenth digit.
I see in Tatianas explanation, she considered 0.50s' tenth digit as 0, but the tenth digit is non-zero which is 5. I beleive for decimals, there is no unit digit and it begins with tenth digit. Correct me if I'm wrong.
I see in Tatianas explanation, she considered 0.50s' tenth digit as 0, but the tenth digit is non-zero which is 5. I beleive for decimals, there is no unit digit and it begins with tenth digit. Correct me if I'm wrong.
- Stuart@KaplanGMAT
- GMAT Instructor
- Posts: 3225
- Joined: Tue Jan 08, 2008 2:40 pm
- Location: Toronto
- Thanked: 1710 times
- Followed by:614 members
- GMAT Score:800
You're 100% correct.ildude02 wrote:The answer is B. 8x will always yield a non zero tenth digit.
I see in Tatianas explanation, she considered 0.50s' tenth digit as 0, but the tenth digit is non-zero which is 5. I beleive for decimals, there is no unit digit and it begins with tenth digit. Correct me if I'm wrong.
If 8x is an integer, and x must be between 0 and 1, then the smallest possible value of x is .125. Every possibly value has a non-zero tenths digit (which is indeed the digit directly to the right of the decimal - the "tens" digit is actually two to the LEFT of the decimal place).
If 16x is an integer, then the smallest possible value of x is .0625, which does have a tenths digit of 0. Of course, x could also be .125, with a non-zero tenths digit; hence, (1) is insufficient.
(2) is sufficient, (1) is not: choose (B).
As a quick review:
2,436.789
2 is the thousands digit
4 is the hundreds digit
3 is the tens digit
6 is the units (or ones) digit
7 is the tenths digit
8 is the hundredths digit
9 is the thousandths digit
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
-
- Master | Next Rank: 500 Posts
- Posts: 167
- Joined: Wed Jun 11, 2008 10:58 pm
- Thanked: 2 times
- Followed by:1 members
@cunu,
had the same doubt...but stuart is spot on...dont look at the answer that ur getting first..u have stated that 8*0.5=4....here, 5 is in the tenths place which is nonzero......dun worry about the answer...
had the same doubt...but stuart is spot on...dont look at the answer that ur getting first..u have stated that 8*0.5=4....here, 5 is in the tenths place which is nonzero......dun worry about the answer...