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 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 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 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.
17 Jan 2014, 04:25
Kudos
Bookmarks
A
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
5%
(low)
Question Stats:
86% (01:07) correct
14%
(01:18)
wrong
based on 120
sessions
History
Date
Time
Result
Not Attempted Yet
If ab < 7, is b < 1?
(1) a > 7
(2) b < 7
My question is:
(1) a > 7
(2) b < 7
My question is:
may I add these inequalities in the way I did or was I just lucky with this approach, and "number picking" is the right approach for these questions to solve them in general? OA explanation suggests number picking for both statements. I feel this is much clearer. Thanks for your comments and help.
Statement 1: 7 < a This tells me "a" is a positive number bigger than 7.
If I add 7 < a to ab < 7, I will get:
ab + 7 < 7 + a deducting on both sides 7
ab < a Normally, I couldn't divide by "a", cause I wouldn't know "a's" sign. But here we are told it is positive and bigger than 7. So I divide by "a" know the inequality sign will not flip.
b < 1 This is what we wanted to prove. SUFFICIENT
Statement 2: This just tells me b is smaller than 7. It could be bigger or smaller than 1.
If I add b < 7 to ab < 7, I will get:
ab + b < 14 I could factor out "b"
b (a +1) < 14 However, this still doesn't help me in anyway to figure out if "b" is smaller than 1. If "a" was say 10 and "b" was 2, then we'd have 22 < 14 which is wrong. If "a" was say 10 and "b" was -1, then we'd have -22 < 14 which would be right. INSUFFICIENT
Statement 1: 7 < a This tells me "a" is a positive number bigger than 7.
If I add 7 < a to ab < 7, I will get:
ab + 7 < 7 + a deducting on both sides 7
ab < a Normally, I couldn't divide by "a", cause I wouldn't know "a's" sign. But here we are told it is positive and bigger than 7. So I divide by "a" know the inequality sign will not flip.
b < 1 This is what we wanted to prove. SUFFICIENT
Statement 2: This just tells me b is smaller than 7. It could be bigger or smaller than 1.
If I add b < 7 to ab < 7, I will get:
ab + b < 14 I could factor out "b"
b (a +1) < 14 However, this still doesn't help me in anyway to figure out if "b" is smaller than 1. If "a" was say 10 and "b" was 2, then we'd have 22 < 14 which is wrong. If "a" was say 10 and "b" was -1, then we'd have -22 < 14 which would be right. INSUFFICIENT
17 Jan 2014, 04:36
Kudos
Bookmarks
BabySmurf
If ab < 7, is b < 1?
1. a > 7
2. b < 7
My question is, may I add these inequalities in the way I did or was I just lucky with this approach, and "number picking" is the right approach for these questions to solve them in general? OA explanation suggests number picking for both statements. I feel this is much clearer. Thanks for your comments and help.
Statement 1: 7 < a This tells me "a" is a positive number bigger than 7.
If I add 7 < a to ab < 7, I will get:
ab + 7 < 7 + a deducting on both sides 7
ab < a Normally, I couldn't divide by "a", cause I wouldn't know "a's" sign. But here we are told it is positive and bigger than 7. So I divide by "a" know the inequality sign will not flip.
b < 1 This is what we wanted to prove. SUFFICIENT
Statement 2: This just tells me b is smaller than 7. It could be bigger or smaller than 1.
If I add b < 7 to ab < 7, I will get:
ab + b < 14 I could factor out "b"
b (a +1) < 14 However, this still doesn't help me in anyway to figure out if "b" is smaller than 1. If "a" was say 10 and "b" was 2, then we'd have 22 < 14 which is wrong. If "a" was say 10 and "b" was -1, then we'd have -22 < 14 which would be right. INSUFFICIENT
1. a > 7
2. b < 7
My question is, may I add these inequalities in the way I did or was I just lucky with this approach, and "number picking" is the right approach for these questions to solve them in general? OA explanation suggests number picking for both statements. I feel this is much clearer. Thanks for your comments and help.
Statement 1: 7 < a This tells me "a" is a positive number bigger than 7.
If I add 7 < a to ab < 7, I will get:
ab + 7 < 7 + a deducting on both sides 7
ab < a Normally, I couldn't divide by "a", cause I wouldn't know "a's" sign. But here we are told it is positive and bigger than 7. So I divide by "a" know the inequality sign will not flip.
b < 1 This is what we wanted to prove. SUFFICIENT
Statement 2: This just tells me b is smaller than 7. It could be bigger or smaller than 1.
If I add b < 7 to ab < 7, I will get:
ab + b < 14 I could factor out "b"
b (a +1) < 14 However, this still doesn't help me in anyway to figure out if "b" is smaller than 1. If "a" was say 10 and "b" was 2, then we'd have 22 < 14 which is wrong. If "a" was say 10 and "b" was -1, then we'd have -22 < 14 which would be right. INSUFFICIENT
Most of the inequality questions, its better to use numbers and solve them, but it also depends on how difficult is the problem.
Here, I guess assumption of numbers is not required as this particular question is fairly simple.
Sometimes, we have 3-5 variables, and at that time, it is advisable to use the numbers to solve it faster.
One more important thing, use numbers to ELIMINATE options and NOT TO SELECT options. It is more of a negative strategy.
17 Jan 2014, 04:37
Kudos
Bookmarks
BabySmurf
If ab < 7, is b < 1?
(1) a > 7
(2) b < 7
My question is, may I add these inequalities in the way I did or was I just lucky with this approach, and "number picking" is the right approach for these questions to solve them in general? OA explanation suggests number picking for both statements. I feel this is much clearer. Thanks for your comments and help.
Statement 1: 7 < a This tells me "a" is a positive number bigger than 7.
If I add 7 < a to ab < 7, I will get:
ab + 7 < 7 + a deducting on both sides 7
ab < a Normally, I couldn't divide by "a", cause I wouldn't know "a's" sign. But here we are told it is positive and bigger than 7. So I divide by "a" know the inequality sign will not flip.
b < 1 This is what we wanted to prove. SUFFICIENT
Statement 2: This just tells me b is smaller than 7. It could be bigger or smaller than 1.
If I add b < 7 to ab < 7, I will get:
ab + b < 14 I could factor out "b"
b (a +1) < 14 However, this still doesn't help me in anyway to figure out if "b" is smaller than 1. If "a" was say 10 and "b" was 2, then we'd have 22 < 14 which is wrong. If "a" was say 10 and "b" was -1, then we'd have -22 < 14 which would be right. INSUFFICIENT
(1) a > 7
(2) b < 7
My question is, may I add these inequalities in the way I did or was I just lucky with this approach, and "number picking" is the right approach for these questions to solve them in general? OA explanation suggests number picking for both statements. I feel this is much clearer. Thanks for your comments and help.
Statement 1: 7 < a This tells me "a" is a positive number bigger than 7.
If I add 7 < a to ab < 7, I will get:
ab + 7 < 7 + a deducting on both sides 7
ab < a Normally, I couldn't divide by "a", cause I wouldn't know "a's" sign. But here we are told it is positive and bigger than 7. So I divide by "a" know the inequality sign will not flip.
b < 1 This is what we wanted to prove. SUFFICIENT
Statement 2: This just tells me b is smaller than 7. It could be bigger or smaller than 1.
If I add b < 7 to ab < 7, I will get:
ab + b < 14 I could factor out "b"
b (a +1) < 14 However, this still doesn't help me in anyway to figure out if "b" is smaller than 1. If "a" was say 10 and "b" was 2, then we'd have 22 < 14 which is wrong. If "a" was say 10 and "b" was -1, then we'd have -22 < 14 which would be right. INSUFFICIENT
Your approach is correct.
ADDING/SUBTRACTING INEQUALITIES:
You can only add inequalities when their signs are in the same direction:
If \(a>b\) and \(c>d\) (signs in same direction: \(>\) and \(>\)) --> \(a+c>b+d\).
Example: \(3<4\) and \(2<5\) --> \(3+2<4+5\).
You can only apply subtraction when their signs are in the opposite directions:
If \(a>b\) and \(c<d\) (signs in opposite direction: \(>\) and \(<\)) --> \(a-c>b-d\) (take the sign of the inequality you subtract from).
Example: \(3<4\) and \(5>1\) --> \(3-5<4-1\).
Adding/subtracting/multiplying/dividing inequalities: help-with-add-subtract-mult-divid-multiple-inequalities-155290.html
Similar question to practice: if-xy-4-is-x-2-1-y-1-2-y-x-129251.html
Hope this helps.
