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.
Jul 1011:00 AM PDT
-11:00 AM PDT
In our conversation, Kishore talks about how strategically he used data analytics to identify high impact areas to focus on as well as his early morning study routine (3 AM prep!) that optimized his GMAT preparation.- Jun 30
08:00 AM PDT
-11:59 PM PDT
Join us June 30th for 2 weeks of GMAT questions (just 8 per day) to help with your prep and to compete with your fellow GMAT Clubbers for a chance to win a prize fund of $30,000 for you and your team-mates! 
Jul 0901:00 PM EDT
-02:00 PM EDT
More Target Test Prep students are earning 100th percentile GMAT scores. Don’t settle for less when the Target Test Prep course gives you everything you need to score high on the GMAT. Start your 5-day free trial today.
Jul 1206:30 AM PDT
-08:30 AM PDT
Join our webinar to master GMAT RC Main Point Questions! Learn effective strategies to decipher passage themes and purposes. Senior Verbal Expert- Sunita Singhvi will equip you with tools to navigate complexities and avoid common traps set by the GMAT.
Jul 1211:00 AM IST
-01:00 PM IST
Attend this session to learn how to Deconstruct arguments, Pre-Think Author’s Assumptions, and apply Negation Test.
Jul 1311:00 AM EDT
-12:30 PM EDT
Looking for your GMAT motivation to break through the score plateau? Pragati improved her score by massive 160 points with strategic guidance and hard-work! Find out how personalized mentorship and a strong mindset can turn GMAT struggles into success.
Jul 1508:00 PM PDT
-09:00 PM PDT
Full-length FE mock with insightful analytics, weakness diagnosis, and video explanations!
Jul 1611:00 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.
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
85%
(hard)
Question Stats:
58% (02:58) correct
42%
(02:26)
wrong
based on 243
sessions
History
Date
Time
Result
Not Attempted Yet
Two missiles are launched simultaneously. Missile 1 launches at a speed of x miles per hour, increasing its speed by a factor of √x every 10 minutes (so that after 10 minutes its speed is x√x, after 20 minutes its speed is x2, and so forth). Missile 2 launches at a speed of y miles per hour, doubling its speed every 10 minutes. After 1 hour, is the speed of Missile 1 greater than that of Missile 2?
(1) x = √y
(2) x > 8
(1) x = √y
(2) x > 8
23 Feb 2012, 23:00
Kudos
Bookmarks
dvinoth86
Two missiles are launched simultaneously. Missile 1 launches at a speed of x miles per hour, increasing its speed by a factor of √x every 10 minutes (so that after 10 minutes its speed is x√x, after 20 minutes its speed is x2, and so forth). Missile 2 launches at a speed of y miles per hour, doubling its speed every 10 minutes. After 1 hour, is the speed of Missile 1 greater than that of Missile 2?
(1) x = √y
(2) x > 8
(1) x = √y
(2) x > 8
After 1 hour the speed of Missile 1 will be \(x*(\sqrt{x})^6=x^4\);
After 1 hour the speed of Missile 2 will be \(y*2^6=64y\);
Question: is \(x^4>64y\)
(1) \(x=\sqrt{y}\). Substitute \(x\), the question becomes: is \((\sqrt{y})^4>64y\)? --> is \(y^2>64y\)? or is \(y>64\)? (since y<0 is not possible). We don't know that. Not sufficient.
(2) \(x > 8\). Clearly insufficient, since no info about y.
(1)+(2) From (2) \(x>8\), which according to (1) means \(\sqrt{y}>8\) --> \(y>64\). Exactly what we wanted to know. Sufficient.
Answer: C.
Another way.
Question: is \(x^4>64y\)
(1) \(x=\sqrt{y}\) --> \(x^2=y\). Substitute \(y\), the question becomes: is \(x^4>64x^2\)? --> is \(x^2>64\)? or is \(x>8\)? (since x<-8 is not possible). We don't know that. Not sufficient.
(2) \(x > 8\). Clearly insufficient, since no info about y.
(1)+(2) From (1) question became "is \(x>8\)?", and (2) \(x>8\) directly answers it. Sufficient.
Answer: C.
Hope it's clear.
23 Feb 2012, 20:54
Kudos
Bookmarks
Answer should be C.
Question: Two missiles are launched simultaneously. Missile 1 launches at a speed of \(x\) miles per hour, increasing its
speed by a factor of \(\sqrt{x}\) every \(10\) minutes (so that after \(10\) minutes its speed is \(x\sqrt{x}\), after \(20\) minutes its speed is \(x^2\), and so forth). Missile 2 launches at a speed of \(y\) miles per hour, doubling its speed every \(10\)
minutes. After \(1\) hour, is the speed of Missile 1 greater than that of Missile 2?
So we know that after \(60\) minutes:
Speed of \(x\) will be \(= x^4\)
Speed of \(y\) will be \(= 64y\)
The question is asking, is \(x^4>64y\) ?
Statement 1: \(x=\sqrt{y}\)
Lets subtitute in \(x^4>64y\):
So the question is asking, is \(y^2>64y\)
Since we know all values are positive, reduce to, is \(y>64\). We have no way to establish this.
Hence Insufficient.
Statement 2: \(x > 8\) . No info about \(y\).
Hence Insufficient.
Combined A&B:
we know that \(x>8\) and we want to find out that \(y>64\) or not.
But \(x=\sqrt{y}\)
So \(\sqrt{y}>8\), so \(y>64\).
Hence Sufficient. Answer C.
Question: Two missiles are launched simultaneously. Missile 1 launches at a speed of \(x\) miles per hour, increasing its
speed by a factor of \(\sqrt{x}\) every \(10\) minutes (so that after \(10\) minutes its speed is \(x\sqrt{x}\), after \(20\) minutes its speed is \(x^2\), and so forth). Missile 2 launches at a speed of \(y\) miles per hour, doubling its speed every \(10\)
minutes. After \(1\) hour, is the speed of Missile 1 greater than that of Missile 2?
So we know that after \(60\) minutes:
Speed of \(x\) will be \(= x^4\)
Speed of \(y\) will be \(= 64y\)
The question is asking, is \(x^4>64y\) ?
Statement 1: \(x=\sqrt{y}\)
Lets subtitute in \(x^4>64y\):
So the question is asking, is \(y^2>64y\)
Since we know all values are positive, reduce to, is \(y>64\). We have no way to establish this.
Hence Insufficient.
Statement 2: \(x > 8\) . No info about \(y\).
Hence Insufficient.
Combined A&B:
we know that \(x>8\) and we want to find out that \(y>64\) or not.
But \(x=\sqrt{y}\)
So \(\sqrt{y}>8\), so \(y>64\).
Hence Sufficient. Answer C.
