Last visit was: 19 Nov 2025, 15:03 It is currently 19 Nov 2025, 15:03
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
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 19 Nov 2025
Posts: 105,390
Own Kudos:
778,363
 [5]
Given Kudos: 99,977
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,390
Kudos: 778,363
 [5]
1
Kudos
Add Kudos
4
Bookmarks
Bookmark this Post
User avatar
GMATinsight
User avatar
Major Poster
Joined: 08 Jul 2010
Last visit: 19 Nov 2025
Posts: 6,839
Own Kudos:
16,354
 [1]
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: 6,839
Kudos: 16,354
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
CareerGeek
Joined: 20 Jul 2017
Last visit: 19 Nov 2025
Posts: 1,292
Own Kudos:
4,272
 [1]
Given Kudos: 162
Location: India
Concentration: Entrepreneurship, Marketing
GMAT 1: 690 Q51 V30
WE:Education (Education)
GMAT 1: 690 Q51 V30
Posts: 1,292
Kudos: 4,272
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
freedom128
Joined: 30 Sep 2017
Last visit: 01 Oct 2020
Posts: 939
Own Kudos:
1,356
 [1]
Given Kudos: 402
GMAT 1: 720 Q49 V40
GPA: 3.8
Products:
GMAT 1: 720 Q49 V40
Posts: 939
Kudos: 1,356
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
(1) z has exactly one prime factor.
z could be 2, 3, 5, 7, 4, 9, 25, 49, etc.
NOT SUFFICIENT

(2) 18 < z < 32, and z has exactly three factors.
Given such range, z must be only 25 (factors of z is 1, 5, 25)
SUFFICIENT

FINAL ANSWER IS (B)
User avatar
shameekv1989
Joined: 14 Dec 2019
Last visit: 17 Jun 2021
Posts: 820
Own Kudos:
986
 [1]
Given Kudos: 354
Location: Poland
Concentration: Entrepreneurship, Strategy
GMAT 1: 640 Q49 V27
GMAT 2: 660 Q49 V31
GMAT 3: 720 Q50 V38
GPA: 4
WE:Engineering (Consumer Electronics)
Products:
GMAT 3: 720 Q50 V38
Posts: 820
Kudos: 986
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
What is the value of the integer z ?

(1) z has exactly one prime factor.
(2) 18 < z < 32, and z has exactly three factors.

Answer - B

Given z is an integer

1) z has exactly one prime factor -> z can me multiple values - 2, 3, 8, 9 etc -> Not sufficient

2) z has exactly 3 factors means z is a perfect square in range 18<z<32 -> Only number is 25 hence z = 25 -> Sufficient
User avatar
eakabuah
User avatar
Retired Moderator
Joined: 18 May 2019
Last visit: 15 Jun 2022
Posts: 776
Own Kudos:
1,125
 [1]
Given Kudos: 101
Posts: 776
Kudos: 1,125
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
We are to determine the value of z, which is an integer.

Statement 1: z has exactly one prime factor
Insufficient. This is because 4, 9, 25, etc all have exactly one prime factor and could be z.

Statement 2: 18<z<32, and z has exactly three factors.
Sufficient. We know that only the square of a prime number has exactly three factors. And the only perfect square that falls within the given range is 25, and that is the square of 5, which is a prime number. Hence z is 25.

The answer is B.

Posted from my mobile device
User avatar
Archit3110
User avatar
Major Poster
Joined: 18 Aug 2017
Last visit: 19 Nov 2025
Posts: 8,422
Own Kudos:
Given Kudos: 243
Status:You learn more from failure than from success.
Location: India
Concentration: Sustainability, Marketing
GMAT Focus 1: 545 Q79 V79 DI73
GMAT Focus 2: 645 Q83 V82 DI81
GPA: 4
WE:Marketing (Energy)
GMAT Focus 2: 645 Q83 V82 DI81
Posts: 8,422
Kudos: 4,982
Kudos
Add Kudos
Bookmarks
Bookmark this Post
#1
z has exactly one prime factor. ; z= 2,4,8,16 .. 5 insufficient
#2
18 < z < 32, and z has exactly three factors.
only perfect squares have three factors ; in this case 25 ; is z
IMO B sufficient

What is the value of the integer z ?

(1) z has exactly one prime factor.
(2) 18 < z < 32, and z has exactly three factors.
avatar
hardikajmani
Joined: 13 Jan 2020
Last visit: 07 Jan 2021
Posts: 14
Own Kudos:
16
 [1]
Given Kudos: 4
Posts: 14
Kudos: 16
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
1) z has exactly one prime factor
Let "a" be the prime factor

possible - values of \( z = {a, a^2, a^3, ...}\)
Insufficient

2) \(18 < z < 32\)
and \(z \)has exactly three factors

Possible values of \(z = 5^2\) with factors \({1, 5, 5^2}\)
Sufficient

Option B
User avatar
ostrick5465
Joined: 30 Jul 2019
Last visit: 09 Nov 2025
Posts: 197
Own Kudos:
222
 [1]
Given Kudos: 71
Location: Viet Nam
WE:Education (Education)
Products:
Posts: 197
Kudos: 222
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
What is the value of the integer z?

(1) z has exactly one prime factor.
(2) 18 < z < 32, and z has exactly three factors.

(1) every prime number has exactly one prime factor.
in range of 18 - 32, there are many prime numbers, such as 19, 23, 29, 31
=> Not suff

(2) z has exactly three factors => z is the square of a prime number
\(3^2 = 9 \)
\(5^2 = 25 \)
\(7^2 =49\)
18< z <32 => z=25

=> Suff

=> Choice B
User avatar
Jawad001
Joined: 14 Sep 2019
Last visit: 10 Nov 2022
Posts: 217
Own Kudos:
152
 [1]
Given Kudos: 31
Posts: 217
Kudos: 152
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
From stmnt (1), Z has many values. Not Sufficient.
From stmnt (2), 25 has only 3 factor .( B)
User avatar
lacktutor
Joined: 25 Jul 2018
Last visit: 23 Oct 2023
Posts: 659
Own Kudos:
1,396
 [1]
Given Kudos: 69
Posts: 659
Kudos: 1,396
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
What is the value of the integer z ?

(Statement1): z has exactly one prime factor.
—> z could be 2,3,9,16,25....
Insufficient

(2) 18 < z < 32, and z has exactly three factors.
—> in order z to have exactly 3 factors, z must be square number.
From 18 to 32, only 25 is a square number—> z = 25
Sufficient

The answer is B

Posted from my mobile device
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,589
Own Kudos:
Posts: 38,589
Kudos: 1,079
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
105390 posts
496 posts