Last visit was: 01 May 2026, 06:28 It is currently 01 May 2026, 06:28
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
Sub 505 (Easy)|   Number Properties|                     
User avatar
KrishnakumarKA1
Joined: 05 Jan 2017
Last visit: 13 Oct 2020
Posts: 398
Own Kudos:
Given Kudos: 15
Location: India
Posts: 398
Kudos: 314
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
mohshu
Joined: 21 Mar 2016
Last visit: 26 Dec 2019
Posts: 410
Own Kudos:
Given Kudos: 103
Products:
Posts: 410
Kudos: 143
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 01 May 2026
Posts: 109,991
Own Kudos:
Given Kudos: 105,972
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,991
Kudos: 812,265
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
CyberStein
Joined: 21 Jun 2017
Last visit: 02 Jun 2023
Posts: 58
Own Kudos:
Given Kudos: 3
Posts: 58
Kudos: 47
Kudos
Add Kudos
Bookmarks
Bookmark this Post
The conditional in this problem (i.e.) "if no flowers are to be left out" is the key to solving; you should interpret this conditional statement as "I need to find the Greatest common divisor among Red and White Tulips.

1. Red Tulips = 91 ; White Tulips = 21
2. To find the Greatest Common Divisor, the quickest method is prime factorization.
3. So, with prime factorization, red tulips = 91 = 7 x 13. White tulips = 21 = 3 x 7.
4. The divisor common in both (7 x 13) and (3 x 7) is 7.

Therefore, the answer to this problem is (E) 7

This problem is on both the 2013 and 2017 GMAT OG.
User avatar
Hoozan
Joined: 28 Sep 2018
Last visit: 30 Dec 2025
Posts: 644
Own Kudos:
Given Kudos: 248
GMAT 1: 660 Q48 V33 (Online)
GMAT 2: 700 Q49 V37
Products:
GMAT 2: 700 Q49 V37
Posts: 644
Kudos: 738
Kudos
Add Kudos
Bookmarks
Bookmark this Post
This is a clear GCF (Greatest Common Factor) question.

There are 21 white and 91 red flowers.

21 = 7 * 3
91 = 7 * 13

we see that 7 is the Greatest Common Factor present in 21 and 91. Hence we can form 7 Identical bouquets out of 21 white and 91 red flowers

Correct (E)

Question

- Bunuel What if we did the LCM (Least Common Multiple)?

I would like to know what happens when we do the LCM of 21 and 91?

LCM (21,91) = 3 * 7 * 21 = 273

What does this 273 represent?
User avatar
chetan2u
User avatar
GMAT Expert
Joined: 02 Aug 2009
Last visit: 01 May 2026
Posts: 11,235
Own Kudos:
Given Kudos: 335
Status:Math and DI Expert
Location: India
Concentration: Human Resources, General Management
GMAT Focus 1: 735 Q90 V89 DI81
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
GMAT Focus 1: 735 Q90 V89 DI81
Posts: 11,235
Kudos: 45,059
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Hoozan
This is a clear GCF (Greatest Common Factor) question.

There are 21 white and 91 red flowers.

21 = 7 * 3
91 = 7 * 13

we see that 7 is the Greatest Common Factor present in 21 and 91. Hence we can form 7 Identical bouquets out of 21 white and 91 red flowers

Correct (E)

Question

- Bunuel What if we did the LCM (Least Common Multiple)?

I would like to know what happens when we do the LCM of 21 and 91?

LCM (21,91) = 3 * 7 * 21 = 273

What does this 273 represent?


For LCM 21=3*7 91=7*13
Find product of all factors but the common should be taken only once
So 3*7*13=273, and 273 is the least common multiple.
That is the least number that will come in multiplication tables of both 21 and 91
User avatar
Ganeshmantri
Joined: 30 Aug 2020
Last visit: 15 Aug 2022
Posts: 23
Own Kudos:
Given Kudos: 95
Location: India
Concentration: Healthcare, General Management
GRE 1: Q168 V157
GPA: 3.36
GRE 1: Q168 V157
Posts: 23
Kudos: 11
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
SOLUTION

What is the greatest number of identical bouquets that can be made out of 21 white and 91 red tulips if no flowers are to be left out? (Two bouquets are identical whenever the number of red tulips in the two bouquets is equal and the number of white tulips in the two bouquets is equal)

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7

Since no flowers are to be left out, then the number of bouquets must be a factor of both 21 and 91. For example, we cannot have 2 bouquets since we cannot divide 91 red tulips into 2 bouquets without one tulip left over.

Only answer choice which is a factor of 91 is E (7).

Answer: E.

Hi Bunuel,

I get that no flowers must be left out. But it is also not mentioned that all the bouquets must be same.
What I mean by thet is that we can form, maybe 20 bouquets if 1 white and 1 red tulip, and another bouquet of 1 white and 71 red tulips. This is the reason why using HCF did not occur to me.

Kindly let me know your thoughts.
I reckon there something seriously wrong with my basocs since nowhere is anyone talking about what I think :| :(

Thanks as always!
Ganesh
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 01 May 2026
Posts: 109,991
Own Kudos:
Given Kudos: 105,972
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,991
Kudos: 812,265
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Ganeshmantri
Bunuel
SOLUTION

What is the greatest number of identical bouquets that can be made out of 21 white and 91 red tulips if no flowers are to be left out? (Two bouquets are identical whenever the number of red tulips in the two bouquets is equal and the number of white tulips in the two bouquets is equal)

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7

Since no flowers are to be left out, then the number of bouquets must be a factor of both 21 and 91. For example, we cannot have 2 bouquets since we cannot divide 91 red tulips into 2 bouquets without one tulip left over.

Only answer choice which is a factor of 91 is E (7).

Answer: E.

Hi Bunuel,

I get that no flowers must be left out. But it is also not mentioned that all the bouquets must be same.
What I mean by thet is that we can form, maybe 20 bouquets if 1 white and 1 red tulip, and another bouquet of 1 white and 71 red tulips. This is the reason why using HCF did not occur to me.

Kindly let me know your thoughts.
I reckon there something seriously wrong with my basocs since nowhere is anyone talking about what I think :| :(

Thanks as always!
Ganesh


I think your doubt is addressed here: https://gmatclub.com/forum/what-is-the- ... l#p1828819 Hope it helps.
User avatar
EMPOWERgmatRichC
User avatar
Major Poster
Joined: 19 Dec 2014
Last visit: 31 Dec 2023
Posts: 21,777
Own Kudos:
Given Kudos: 450
Status:GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Expert
Expert reply
GMAT 1: 800 Q51 V49
GRE 1: Q170 V170
Posts: 21,777
Kudos: 13,060
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Ganeshmantri
Bunuel
SOLUTION

What is the greatest number of identical bouquets that can be made out of 21 white and 91 red tulips if no flowers are to be left out? (Two bouquets are identical whenever the number of red tulips in the two bouquets is equal and the number of white tulips in the two bouquets is equal)

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7

Since no flowers are to be left out, then the number of bouquets must be a factor of both 21 and 91. For example, we cannot have 2 bouquets since we cannot divide 91 red tulips into 2 bouquets without one tulip left over.

Only answer choice which is a factor of 91 is E (7).

Answer: E.

Hi Bunuel,

I get that no flowers must be left out. But it is also not mentioned that all the bouquets must be same.
What I mean by thet is that we can form, maybe 20 bouquets if 1 white and 1 red tulip, and another bouquet of 1 white and 71 red tulips. This is the reason why using HCF did not occur to me.

Kindly let me know your thoughts.
I reckon there something seriously wrong with my basocs since nowhere is anyone talking about what I think :| :(

Thanks as always!
Ganesh

Hi Ganesh,

The key word in this prompt is "IDENTICAL" (meaning that the bouquets must have the SAME flowers in it) - and the wording in the parentheses explains how a bouquet is identical with another bouquet as long as the number and type of flowers are the same.

For example:
A bouquet with 1 red flower and 1 white flower is the SAME as a bouquet with 1 white flower and 1 red flower
So RW and WR are the SAME bouquet

Another example:
RRW, RWR and WRR are all the SAME bouquet

GMAT assassins aren't born, they're made,
Rich
User avatar
totaltestprepNick
Joined: 25 Aug 2014
Last visit: 28 Apr 2026
Posts: 469
Own Kudos:
Given Kudos: 2
GMAT 1: 750 Q49 V42
GMAT 1: 750 Q49 V42
Posts: 469
Kudos: 4
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel
What is the greatest number of identical bouquets that can be made out of 21 white and 91 red tulips if no flowers are to be left out? (Two bouquets are identical whenever the number of red tulips in the two bouquets is equal and the number of white tulips in the two bouquets is equal)

(A) 3
(B) 4
(C) 5
(D) 6
(E) 7





Nick Slavkovich, GMAT/GRE tutor with 20+ years of experience

[email protected]
   1   2 
Moderators:
Math Expert
109991 posts
Tuck School Moderator
852 posts