GRE Prep 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 25Crafting an Impactful Resume: Balancing Detail with Brevity
10:00 AM EDT
-10:30 AM EDT
Showcase your achievements through impactful storytelling! Get ready for an LIVE session on April 25, Learn how to craft compelling narratives on your resume that resonate with admission committees.
Apr 26Get a Top GRE Score with Target Test Prep
12:00 PM EDT
-01:00 PM EDT
The Target Test Prep course represents a quantum leap forward in GRE preparation, a radical reinterpretation of the way that students should study. In fact, more and more Target Test Prep students are scoring 329 and above on the GRE.
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Given Kudos: 172
Location: India
WE:Education (Education)
x is an integer such that 1 ≤ x ≤ 100
[#permalink]
22 Aug 2021, 23:20
22 Aug 2021, 23:20
1
16
Bookmarks
00:00
Question Stats:
19% (02:23) correct
80% (02:23) wrong based on 63 sessions
Hide Show timer Statistics
\(x\) is an integer such that \(1 ≤ x ≤ 100\)
A. Quantity A is greater
B. Quantity B is greater
C. The two quantities are equal
D. The relationship cannot be determined from the information given
Quantity A |
Quantity B |
Probability that \(x(x + 1)\) is a multiple of 12 and 9 |
\(\frac{1}{10}\) |
A. Quantity A is greater
B. Quantity B is greater
C. The two quantities are equal
D. The relationship cannot be determined from the information given
Re: x is an integer such that 1 x 100
[#permalink]
30 Mar 2022, 03:19
30 Mar 2022, 03:19
3
1
Bookmarks
It took some time, I hope my solution is correct.
To be divisible by 9 and 12 means to be divisible by 2*2*3*3 (LCM). Which means that the original pair of numbers should be divisible by 12 and 3 or by 9 and 4 or by 6 and 6. As it is impossible for two neighbor number to be divisible by 6, we have not to examine this case. If we list all number that are divisible by 12 in given range, no neighbor number is divisible by 3. If we list all numbers divisible by 9, there are 5 pairs where neighbor number can be divided by 4, namely pairs: (8,9)(27,28)(44,45)(63,64)(91,92). Which means there are 5 pairs that satisfy the question. Overall there are 100/2=50 possible pairs in the given range, therefore answer is 5/50=1/10, which means correct choice is C
To be divisible by 9 and 12 means to be divisible by 2*2*3*3 (LCM). Which means that the original pair of numbers should be divisible by 12 and 3 or by 9 and 4 or by 6 and 6. As it is impossible for two neighbor number to be divisible by 6, we have not to examine this case. If we list all number that are divisible by 12 in given range, no neighbor number is divisible by 3. If we list all numbers divisible by 9, there are 5 pairs where neighbor number can be divided by 4, namely pairs: (8,9)(27,28)(44,45)(63,64)(91,92). Which means there are 5 pairs that satisfy the question. Overall there are 100/2=50 possible pairs in the given range, therefore answer is 5/50=1/10, which means correct choice is C
