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

 It is currently 22 Oct 2019, 12:32

### 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

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

# If y is a positive integer, what is the units digit of y?

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 27 Dec 2016
Posts: 309
If y is a positive integer, what is the units digit of y?  [#permalink]

### Show Tags

29 Sep 2017, 19:53
1
00:00

Difficulty:

15% (low)

Question Stats:

76% (00:51) correct 24% (01:02) wrong based on 91 sessions

### HideShow timer Statistics

If y is a positive integer, what is the units digit of y?

(1) The units digit of y^2 = 1
(2) The units digit of y does not equal 1

Source: Manhattan
Senior Manager
Joined: 17 Oct 2016
Posts: 310
Location: India
Concentration: Operations, Strategy
GPA: 3.73
WE: Design (Real Estate)
Re: If y is a positive integer, what is the units digit of y?  [#permalink]

### Show Tags

29 Sep 2017, 20:01
C

St1 says y can be an integer with unit digit 9 or 1

St2 clearly not sufficient.

Combining we can conclude the unit digit is 9. Hence C

Sent from my iPhone using GMAT Club Forum
_________________
Help with kudos if u found the post useful. Thanks
Director
Joined: 09 Mar 2018
Posts: 994
Location: India
Re: If y is a positive integer, what is the units digit of y?  [#permalink]

### Show Tags

07 Feb 2019, 23:17
csaluja wrote:
If y is a positive integer, what is the units digit of y?

(1) The units digit of y^2 = 1
(2) The units digit of y does not equal 1

Source: Manhattan

Keyword : y is a positive integer

UD of y

from 1, we can get 2 values 9 and 1

from 2, we can get 8 values

Combination will give us an unique value, i.e. 1

C
_________________
If you notice any discrepancy in my reasoning, please let me know. Lets improve together.

Quote which i can relate to.
Many of life's failures happen with people who do not realize how close they were to success when they gave up.
Intern
Joined: 13 Jul 2019
Posts: 26
Re: If y is a positive integer, what is the units digit of y?  [#permalink]

### Show Tags

26 Aug 2019, 23:25
Hi,

This is a pretty simple question if you know about cyclicity. If not, read about cyclicity of numbers before seeing the solution below.

We know y is a positive integer.
Question asks for the units digit of y.

We need to have value of y or some relationship to know about the units digit of y.

Statement 1: Units digit of $$y^2$$ = 1
This is possible only if units digit of y = 1 or 9
Two possible values

Insufficient

Statement 2: Units digit of $$y\neq{1}$$
=> y = 2, 3, 4, 5, 6, 7, 8, 9, 0

Insufficient

Combine the information from both the statements. We get only 1 value i.e. 1.

Sufficient

Please give kudos if you liked the solution.

Deepti Singh
Master Trainer - GMAT
Manya - The Princeton Review
Re: If y is a positive integer, what is the units digit of y?   [#permalink] 26 Aug 2019, 23:25
Display posts from previous: Sort by