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 2301:30 AM EDT
-02:30 AM EDT
Struggling with GMAT Verbal as a non-native speaker? Harsh improved his score from 595 to 695 in just 45 days—and scored a 99 %ile in Verbal (V88)! Learn how smart strategy, clarity, and guided prep helped him gain 100 points.
Apr 2308:00 PM PDT
-09:00 PM PDT
Video explanations + diagnosis of 10 weakest areas + 150+ short videos + study plan!
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.
19 Feb 2016, 21:47
Kudos
Bookmarks
C
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
75%
(hard)
Question Stats:
62% (02:31) correct
38%
(02:18)
wrong
based on 317
sessions
History
Date
Time
Result
Not Attempted Yet
Two persons A and B run at constant speeds of a miles per hour and b miles per hour respectively. They start running toward each other at the same time from a distance of d miles. What is the speed of A and B?
(1) If A and B ran at speeds of a/2 and 2b respectively, they would take the same amount of time to meet.
(2) If they both ran at 1 mile per hour slower, they would take double the time to meet.
(1) If A and B ran at speeds of a/2 and 2b respectively, they would take the same amount of time to meet.
(2) If they both ran at 1 mile per hour slower, they would take double the time to meet.
21 Feb 2016, 12:54
Kudos
Bookmarks
1. d/(a+b)=d/((a/2)+2b) => 2b=a ( not sufficient)
2. d/(a+b-2)=2* d/(a+b) => a+b=4 ( not sufficient)
combining => we can solve for a and b.
=> C
2. d/(a+b-2)=2* d/(a+b) => a+b=4 ( not sufficient)
combining => we can solve for a and b.
=> C
23 Feb 2016, 19:00
Kudos
Bookmarks
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.
Two persons A and B run at constant speeds of a miles per hour and b miles per hour respectively. They start running toward each other at the same time from a distance of d miles. What is the speed of A and B?
(1) If A and B ran at speeds of a/2 and 2b respectively, they would take the same amount of time to meet.
(2) If they both ran at 1 mile per hour slower, they would take double the time to meet.
When you modify the original condition and the question, they become at+bt=d.(t is a time until they meet) That is, there are 4 variables(a,b,t,d) and 1 equation((a+b)t=d), which should match with the number of equations. So you need 3 more equations. For 1) 1 equation, For 2) 1 equation, which is likely to make E the answer.
When 1 & 2), they make (a/2+b)t=d, (a+b-2)2t=d and a+b=2a+2b-4, a/2+b=a+2b -> a=2b -> b=4/3, a=8/3, which is unique and sufficient.
Thus, C is the answer.
For cases where we need 3 more equations, such as original conditions with “3 variables”, or “4 variables and 1 equation”, or “5 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 80% chance that E is the answer (especially about 90% of 2 by 2 questions where there are more than 3 variables), while C has 15% chance. These two are the majority. In case of common mistake type 3,4, the answer may be from A, B or D but there is only 5% chance. Since E is most likely to be the answer using 1) and 2) separately according to DS definition (It saves us time). Obviously there may be cases where the answer is A, B, C or D.
Two persons A and B run at constant speeds of a miles per hour and b miles per hour respectively. They start running toward each other at the same time from a distance of d miles. What is the speed of A and B?
(1) If A and B ran at speeds of a/2 and 2b respectively, they would take the same amount of time to meet.
(2) If they both ran at 1 mile per hour slower, they would take double the time to meet.
When you modify the original condition and the question, they become at+bt=d.(t is a time until they meet) That is, there are 4 variables(a,b,t,d) and 1 equation((a+b)t=d), which should match with the number of equations. So you need 3 more equations. For 1) 1 equation, For 2) 1 equation, which is likely to make E the answer.
When 1 & 2), they make (a/2+b)t=d, (a+b-2)2t=d and a+b=2a+2b-4, a/2+b=a+2b -> a=2b -> b=4/3, a=8/3, which is unique and sufficient.
Thus, C is the answer.
For cases where we need 3 more equations, such as original conditions with “3 variables”, or “4 variables and 1 equation”, or “5 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 80% chance that E is the answer (especially about 90% of 2 by 2 questions where there are more than 3 variables), while C has 15% chance. These two are the majority. In case of common mistake type 3,4, the answer may be from A, B or D but there is only 5% chance. Since E is most likely to be the answer using 1) and 2) separately according to DS definition (It saves us time). Obviously there may be cases where the answer is A, B, C or D.
