Events & Promotions
|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Apr 2512:30 AM EDT
-01:30 AM EDT
At one point, she believed GMAT wasn’t for her. After scoring 595, self-doubt crept in and she questioned her potential. But instead of quitting, she made the right strategic changes. The result? A remarkable comeback to 695. Check out how Saakshi did it.
Apr 2610:00 AM EDT
-11:00 AM EDT
The Target Test Prep course represents a quantum leap forward in GMAT preparation, a radical reinterpretation of the way that students should study. Try before you buy with a 5-day, full-access trial of the course for FREE!
Apr 2711:00 AM EDT
-12:00 PM EDT
Prefer video-based learning? The Target Test Prep OnDemand course is a one-of-a-kind video masterclass featuring 400 hours of lecture-style teaching by Scott Woodbury-Stewart, founder of Target Test Prep and one of the most accomplished GMAT instructors
Apr 2808:00 AM PDT
-11:00 AM PDT
Whether you are just beginning your MBA journey or fine-tuning your path to a 700+ score, GMAT Day is designed to give you a competitive edge.
09 Jun 2024, 23:21
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
65%
(hard)
Question Stats:
55% (01:52) correct
45%
(01:51)
wrong
based on 349
sessions
History
Date
Time
Result
Not Attempted Yet
If x and y are positive integers, which of the following cannot be the highest common factor of 21x and 35y?
A. 7
B. 21
C. x - y
D. x + y
E. 21y
Source: Experts' Global
A. 7
B. 21
C. x - y
D. x + y
E. 21y
Source: Experts' Global
10 Jun 2024, 00:28
Kudos
Bookmarks
LamboWalker
21x = 7(3x) and 35y = 7(5y). Thus, the highest common factor of the two numbers must include 7.
Let's check the options:
A. 7
For 7 to be the HCF of 7(3x) and 7(5y), 3x and 5y must be co-prime; they should not share any common factor except 1. Consequently, since 3 and 5 are already co-prime, x and y should be co-prime. For example, if x = 1 and y = 1, 7 would be the HCF of 21 and 35.
B. 21
If y is a multiple of 3 (and it does not share a common factor with x), then 21 will be the HCF of 7(3x) and 7(5y). For example, consider x = 1 and y = 3.
C. x - y
This could happen, for example, when x and y are co-prime such that x is not a multiple of 5 and y is not a multiple of 3, and x - y = 7. For example, consider x = 8 and y = 1.
D. x + y
Similarly, this could happen, for example, when x and y are co-prime such that x is not a multiple of 5 and y is not a multiple of 3, and x + y = 7. For example, consider x = 6 and y = 1.
E. 21y
21y cannot be the HCF since it's not a factor of 35y: 35y/(21y) = 5/3, which is not an integer.
Answer: E.
General Discussion
01 Jul 2025, 22:25
Kudos
Bookmarks
Please edit the question ;
21x and 35y it can be x&y unit digits
21x and 35y it can be x&y unit digits
