Last visit was: 20 Jul 2025, 12:13 It is currently 20 Jul 2025, 12:13
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
Sub 505 Level|   Fractions and Ratios|   Inequalities|   Number Properties|                     
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 20 Jul 2025
Posts: 102,633
Own Kudos:
Given Kudos: 98,235
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 102,633
Kudos: 743,055
 [24]
3
Kudos
Add Kudos
21
Bookmarks
Bookmark this Post
Most Helpful Reply
User avatar
pushpitkc
Joined: 26 Feb 2016
Last visit: 19 Feb 2025
Posts: 2,819
Own Kudos:
5,876
 [8]
Given Kudos: 47
Location: India
GPA: 3.12
Posts: 2,819
Kudos: 5,876
 [8]
8
Kudos
Add Kudos
Bookmarks
Bookmark this Post
General Discussion
User avatar
BrentGMATPrepNow
User avatar
Major Poster
Joined: 12 Sep 2015
Last visit: 13 May 2024
Posts: 6,755
Own Kudos:
34,143
 [3]
Given Kudos: 799
Location: Canada
Expert
Expert reply
Posts: 6,755
Kudos: 34,143
 [3]
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
MarkusKarl
Joined: 15 Mar 2015
Last visit: 22 Oct 2017
Posts: 87
Own Kudos:
Given Kudos: 7
Posts: 87
Kudos: 67
Kudos
Add Kudos
Bookmarks
Bookmark this Post
We need to find the unit digits of both (or one if its 0).

I - 4 multipels can generate 4 or 8 as two examples - no need to look further. NS

II - 7 multipels can generate 7 or 14, 7>5; 4<5. NS

Together:
4*7=28 8>5. Sufficient.
C

Posted from my mobile device
User avatar
RaguramanS
Joined: 17 Feb 2016
Last visit: 09 Feb 2018
Posts: 71
Own Kudos:
Given Kudos: 59
Location: India
Concentration: General Management, Entrepreneurship
GMAT 1: 660 Q47 V36
GPA: 3.12
WE:Education (Internet and New Media)
Products:
GMAT 1: 660 Q47 V36
Posts: 71
Kudos: 158
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If a is a 3-digit integer and b is a 3-digit integer, is the units digit of the product of a and b greater than 5?

Unit digit of A*B>5
Let x,y = unit digit of a and b

(1) The units digit of a is 4.
If y=2, x*y= 8
If y=1, x*y= 4
NS

(2) The units digit of b is 7
If x= 3, x*y = 21 ( unit digit is 1)
If x= 4, x*y = 28 ( unit digit is 8)
NS

St 1+2. Suff x*y= 28 ( unit digit is 8 )

Option C
User avatar
akshayk
Joined: 06 Jul 2016
Last visit: 21 Sep 2020
Posts: 273
Own Kudos:
Given Kudos: 99
Location: Singapore
Concentration: Strategy, Finance
Posts: 273
Kudos: 402
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If a is a 3-digit integer and b is a 3-digit integer, is the units digit of the product of a and b greater than 5?

(1) The units digit of a is 4.
(2) The units digit of b is 7.

a = xyz
b = def
z*f = gh , where h is the unit's digit of z*f
=> h > 5 ?

1) z = 4, f = 1
z*f = 4 => h = 4
NO
But z = 4, f = 2
z*f = 8 => h = 8
YES
Insufficient.


2) f = 7, z = 1
f*z = 7 => h = 7
YES
But, z = 2, f = 7
f*z = 14 => h = 4
NO
Insufficient

1+2)
f = 7 , z = 4
z*f = 28
h > 5 => YES
Sufficient.

C is the answer.
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 20 Jul 2025
Posts: 21,145
Own Kudos:
26,207
 [1]
Given Kudos: 296
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 21,145
Kudos: 26,207
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If a is a 3-digit integer and b is a 3-digit integer, is the units digit of the product of a and b greater than 5?

(1) The units digit of a is 4.
(2) The units digit of b is 7.

We are given that a is a 3-digit integer and b is a 3-digit integer and need to determine whether the product of a and b is greater than 5.

Statement One Alone:

The units digit of a is 4.

Statement one alone is not sufficient to answer the question. For example, if the units digit of b is 1, then the units digit of the product of a and b is 4, which is less than 5; however, if the units digit of b is 2, then the units digit of the product of a and b is 8, which is greater than 5.

Statement Two Alone:

The units digit of b is 7.

Statement two alone is not sufficient to answer the question. For example, if the units digit of a is 1, then the units digit of the product of a and b is 7, which is greater than 5; however, if the units digit of a is 0, then the units digit of the product of a and b is 0, which is less than 5.

Statements One and Two Together:

Using the information from statements one and two, we see that since the product of the units digits of a and b is 4 x 7 = 28, the units digit of the product of a and b is 8, which is greater than 5.

Answer: C
User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 20 Jul 2025
Posts: 6,378
Own Kudos:
Given Kudos: 128
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Products:
Expert
Expert reply
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
Posts: 6,378
Kudos: 15,617
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
If a is a 3-digit integer and b is a 3-digit integer, is the units digit of the product of a and b greater than 5?

(1) The units digit of a is 4.
(2) The units digit of b is 7.

Answer: Option C

Video solution by GMATinsight

User avatar
NightWalker
Joined: 24 Nov 2019
Last visit: 09 Jun 2023
Posts: 144
Own Kudos:
Given Kudos: 132
Concentration: Strategy, International Business
GMAT 1: 760 Q51 V41 (Online)
GMAT 1: 760 Q51 V41 (Online)
Posts: 144
Kudos: 51
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Let a= xyz and b= abc

Units digit of the product of the numbers above will have component of z*c
therefore, question is the unit digit of z*c >5

C: Both statements are necessary.
User avatar
avigutman
Joined: 17 Jul 2019
Last visit: 15 Jul 2025
Posts: 1,294
Own Kudos:
Given Kudos: 66
Location: Canada
GMAT 1: 780 Q51 V45
GMAT 2: 780 Q50 V47
GMAT 3: 770 Q50 V45
Expert
Expert reply
GMAT 3: 770 Q50 V45
Posts: 1,294
Kudos: 1,897
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Video solution from Quant Reasoning:
Subscribe for more: https://www.youtube.com/QuantReasoning? ... irmation=1
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 37,463
Own Kudos:
Posts: 37,463
Kudos: 1,013
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
Moderators:
Math Expert
102633 posts
455 posts