GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 25 Aug 2019, 21:54

### 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

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Author Message
TAGS:

### Hide Tags

Manager
Joined: 07 May 2007
Posts: 157

### Show Tags

01 Jul 2007, 09:43
1
14
00:00

Difficulty:

55% (hard)

Question Stats:

67% (02:33) correct 33% (02:23) wrong based on 292 sessions

### HideShow timer Statistics

To receive a driver license, sixteen year-olds at Culliver High School have to pass both a written and a practical driving test. Everyone has to take the tests, and no one failed both tests. If 30% of the 16 year-olds who passed the written test did not pass the practical, how many sixteen year-olds at Culliver High School received their driver license?

(1) There are 188 sixteen year-olds at Culliver High School.

(2) 20% of the sixteen year-olds who passed the practical test failed the written test.
Manager
Joined: 03 Mar 2007
Posts: 146

### Show Tags

01 Jul 2007, 11:22
4
I got C.

Just did a Vinn Diagram.

You are given:

to get a license you have to pass BOTH which is the overlap of the two circles.

Also, no one failed both so nothing outside circles.

30% W but not P.

Statement 1: 188 total 16 year olds. INSUFF.

Statement 2: 20% P but not W.

So this tells you that the overlap is 50% of total 16 yr olds. But the question wants a definite number, if it had said what % of 16 got a license then 2 would be sufficient. INSUFF.

together you know there are 188 total 16 year olds and 50% got their license so 94 got their license. C.

What is the OA?
Intern
Joined: 02 Apr 2008
Posts: 33

### Show Tags

20 Apr 2008, 14:18
1

(1) insufficient
(2) insufficient because it doesn't give details as to the total number of students

Combined,
w - % of 188 who passed the written test
p - % of 188 who passed the practical tests
0.3w -failed practical test
0.2p - failed written test

first equation 0.3w +0.7w+0.2p =188 --> w+0.2p =188
second equation p+0.3w=188

2 variables with 2 equations, which means you can find the answer
Current Student
Joined: 28 Dec 2004
Posts: 2984
Location: New York City
Schools: Wharton'11 HBS'12

### Show Tags

20 Apr 2008, 16:26
1
I am going to say E on this..cause while i know the number of 16-year olds..i dont know how many actually applied for the drivers license..this question as is written would be E..

anyone else have the same view as I?
Intern
Joined: 07 Nov 2007
Posts: 23
Location: Dominican Republic

### Show Tags

21 Apr 2008, 17:30
fresinha12 wrote:
I am going to say E on this..cause while i know the number of 16-year olds..i dont know how many actually applied for the drivers license..this question as is written would be E..

anyone else have the same view as I?

The question stem says that all students must take the tests.
Current Student
Joined: 28 Dec 2004
Posts: 2984
Location: New York City
Schools: Wharton'11 HBS'12

### Show Tags

22 Apr 2008, 15:08
chineseburned wrote:
To receive a driver license, sixteen year-olds at Culliver High School have to pass both a written and a practical driving test. Everyone has to take the tests, and no one failed both tests. If 30% of the 16 year-olds who passed the written test did not pass the practical, how many sixteen year-olds at Culliver High School received their driver license?

(1) There are 188 sixteen year-olds at Culliver High School.

(2) 20% of the sixteen year-olds who passed the practical test failed the written test.

Man this is hard..

p=% passed practical
w=% passed written..

(1-p)=.3W from the stem

1) 188 students insuff, (2) (1-w)=0.2p

P+(1-p)+w+(1-w)=188

p+.3W+w+0.2p=188

1.2p+1.3W=188

I dont get..how this can be C? i have 2 variables 1 equation..

can someone explain?
Intern
Joined: 07 Nov 2007
Posts: 23
Location: Dominican Republic

### Show Tags

22 Apr 2008, 19:47
1
I used a different approach and got C as the answer, but I'm not sure if my value answer holds true. Basically I got that 50% of the students involved in the tests got their driver's license.

This means that 188/2 = 94 students got their license instead of 112.
Attachments

Untitled.jpg [ 9.55 KiB | Viewed 6928 times ]

SVP
Joined: 24 Aug 2006
Posts: 2064

### Show Tags

23 Apr 2008, 11:58
1
A+B+C=188

.3(a+b)=a

.2(b+c)=c

solve for B, which equals 112
Attachments

VENN.JPG [ 33.54 KiB | Viewed 6911 times ]

Manager
Joined: 06 Feb 2010
Posts: 145
Schools: University of Dhaka - Class of 2010
GPA: 3.63

### Show Tags

12 Nov 2013, 08:43
2
2
To receive a driver license, sixteen year-olds at Culliver High School have to pass both a written and a practical driving test. Everyone has to take the tests, and no one failed both tests. If 30% of the 16 year-olds who passed the written test did not pass the practical, how many sixteen year-olds at Culliver High School received their driver license?

(1) There are 188 sixteen year-olds at Culliver High School.

(2) 20% of the sixteen year-olds who passed the practical test failed the written test.
_________________
Practice Makes a Man Perfect. Practice. Practice. Practice......Perfectly

Critical Reasoning: http://gmatclub.com/forum/best-critical-reasoning-shortcuts-notes-tips-91280.html

Collections of MGMAT CAT: http://gmatclub.com/forum/collections-of-mgmat-cat-math-152750.html

MGMAT SC SUMMARY: http://gmatclub.com/forum/mgmat-sc-summary-of-fourth-edition-152753.html

Sentence Correction: http://gmatclub.com/forum/sentence-correction-strategies-and-notes-91218.html

Arithmatic & Algebra: http://gmatclub.com/forum/arithmatic-algebra-93678.html

I hope these will help to understand the basic concepts & strategies. Please Click ON KUDOS Button.
Senior Manager
Status: busyness school student
Joined: 09 Sep 2013
Posts: 416
Location: United States
Schools: Tepper '16 (M)
GMAT 1: 730 Q52 V37

### Show Tags

12 Nov 2013, 09:17
There are four outcomes. You can:
A) Pass Written and Pass Practical (which implies you get a license)
B) Pass Written and Fail Practical
C) Fail Written and Pass Practical
D) Fail Written and Fail Practical.

We are given that no one (0%) has failed both (outcome D) and that 30% Pass written, Fail practical (outcome B).
We need to find the number corresponding to outcome A (not the percentage!)

(1) There are 188 sixteen year-olds at Culliver High School.
Great, this tells you that 0 kids fall into outcome D and 57 kids fall into outcome B. But this doesn't tell you how many fall into outcome A. It tells you that the total number of kids in outcome A and outcome C is 188-57=131.

(2) 20% of the sixteen year-olds who passed the practical test failed the written test.
We now know that 20% are in outcome C. Since we know the % of kids in outcomes B, C, and D, we can figure out the % of kids in outcome A. There are 50% of kids in outcome A, since outcomes B+C+D = 50%. But, this still doesn't tell how many students are in outcome A, just the percentage.

Given both (1) and (2), we now know that 50% of 188 students (or 94 students) passed both the written and practical exam.

_________________
Math Expert
Joined: 02 Sep 2009
Posts: 57255

### Show Tags

12 Nov 2013, 10:43
monirjewel wrote:
To receive a driver license, sixteen year-olds at Culliver High School have to pass both a written and a practical driving test. Everyone has to take the tests, and no one failed both tests. If 30% of the 16 year-olds who passed the written test did not pass the practical, how many sixteen year-olds at Culliver High School received their driver license?

(1) There are 188 sixteen year-olds at Culliver High School.

(2) 20% of the sixteen year-olds who passed the practical test failed the written test.

Merging similar topics. Please search before posting.
_________________
Director
Status: Everyone is a leader. Just stop listening to others.
Joined: 22 Mar 2013
Posts: 727
Location: India
GPA: 3.51
WE: Information Technology (Computer Software)

### Show Tags

11 Apr 2014, 05:10
2
1
Clearly 1 and 2 are not sufficient.

Using both options it is possible to find out the answer.

Attachment:

Question.jpg [ 39.46 KiB | Viewed 5879 times ]

_________________
Piyush K
-----------------------
Our greatest weakness lies in giving up. The most certain way to succeed is to try just one more time. ― Thomas A. Edison
Don't forget to press--> Kudos
My Articles: 1. WOULD: when to use? | 2. All GMATPrep RCs (New)
Tip: Before exam a week earlier don't forget to exhaust all gmatprep problems specially for "sentence correction".
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 7766
GMAT 1: 760 Q51 V42
GPA: 3.82

### Show Tags

26 Nov 2015, 08:07
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.

To receive a driver license, sixteen year-olds at Culliver High School have to pass both a written and a practical driving test. Everyone has to take the tests, and no one failed both tests. If 30% of the 16 year-olds who passed the written test did not pass the practical, how many sixteen year-olds at Culliver High School received their driver license?

(1) There are 188 sixteen year-olds at Culliver High School.

(2) 20% of the sixteen year-olds who passed the practical test failed the written test.

This is a "2by2" question, one of the most common type of question in GMAT math
we get a table as below:
Attachment:

GCDS iamba To receive a driver license (20151126).jpg [ 44.75 KiB | Viewed 4785 times ]

There are 3 variables (a,b,c) and one equation (c=0.3(a+c)) in the original condition, and 2 equations are given by the conditions, so there is high chance (C) will be the answer
Looking at the conditions together,
a+b+c=188, b=0.2(a+b), and this is sufficient to achieve an answer,

For cases where we need 2 more equations, such as original conditions with “2 variables”, or “3 variables and 1 equation”, or “4 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 70% chance that C is the answer, while E has 25% 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 C 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, D or E.
_________________
MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only \$79 for 1 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"
Intern
Joined: 01 Jun 2018
Posts: 24
Location: Viet Nam
Schools: Mays '21
GMAT 1: 710 Q50 V34

### Show Tags

10 Aug 2018, 01:19
It's C. There were 112 having the driving licence. 140 passed the practical test including 28 (20% of 140) did not pass the writing (hence 112 passed both), 160 passed the writing test including 48 (30% of 160) did not pass the practical test. 112 + 28 + 48 = 188, which left us 0 person who failed both test as indicated.
PiyushK solution can help determine these values.
Hope this help!
Non-Human User
Joined: 09 Sep 2013
Posts: 12092

### Show Tags

24 Aug 2019, 01:39
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Display posts from previous: Sort by