Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 30 Jun 2016, 04:22

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Intern
Joined: 22 Jan 2008
Posts: 2
Followers: 0

Kudos [?]: 1 [1] , given: 0

### Show Tags

27 Jan 2008, 13:16
1
KUDOS
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Hello, can somebody please help me solve the following 5 questions. Thank you very much.

1. What is the greatest prime factor of 4^17 – 2^28?
The correct answer is 7.

2. If K is a positive integer, is K the square of an integer?
i) K is divisible by 4
ii) K is divisible exactly by 4 different prime numbers.
The correct answer is e, statement i and ii together are NOT sufficient.

3. The symbol * represents one of four arithmetic options, plus, minus, divide, or multiply. Is (5*6)*2 = 5*(6*2)?
i) 5*6 = 6*6
ii) 2*0 = 2
The correct answer is a, statement i alone is sufficient.

4. Five pieces of wood have an average length of 124 cm and a median length of 140cm. what is the maximum possible length of the shortest piece of wood?
The correct answer is 100cm

5. Machine A produces pencils at a constant rate of 9000/hour. Machine B produces pencils at a constant rate of 7000/hour. If the two machines together must produce 100,000 pencils, and if each machine can operate for at most 8 hours, what is the least amount of time that machine B must operate.
The correct answer is 4 hours.
CEO
Joined: 17 Nov 2007
Posts: 3580
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 485

Kudos [?]: 2802 [2] , given: 359

### Show Tags

27 Jan 2008, 13:25
2
KUDOS
Expert's post
Please, post the problems separately...

leizermike wrote:
1. What is the greatest prime factor of 4^17 – 2^28?
The correct answer is 7.

$$4^{17}-2^{28}=2^{34}-2^{28}=2^{28}*(2^6-1)=2^{28}*63=2^{28}*3^2*7$$
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

CEO
Joined: 17 Nov 2007
Posts: 3580
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 485

Kudos [?]: 2802 [0], given: 359

### Show Tags

27 Jan 2008, 13:28
Expert's post
leizermike wrote:
2. If K is a positive integer, is K the square of an integer?
i) K is divisible by 4
ii) K is divisible exactly by 4 different prime numbers.
The correct answer is e, statement i and ii together are NOT sufficient.

$$K=2^2*3^2*5^2*7$$ and $$K=2^2*3^2*5^2*7^2$$ are satisfy both conditions but only one is the square of an integer. E
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

CEO
Joined: 17 Nov 2007
Posts: 3580
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 485

Kudos [?]: 2802 [0], given: 359

### Show Tags

27 Jan 2008, 13:34
Expert's post
leizermike wrote:
3. The symbol * represents one of four arithmetic options, plus, minus, divide, or multiply. Is (5*6)*2 = 5*(6*2)?
i) 5*6 = 6*6
ii) 2*0 = 2
The correct answer is a, statement i alone is sufficient.

I think It have to be 5*6=6*5.

(5*6)*2 = 5*(6*2) is true for "+", "*" and is false for "-", "/"

1. 5*6=6*5 is true for "+", "*". sufficient.

2. 2*0=2 is true for "+", "-".insufficient.
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

CEO
Joined: 17 Nov 2007
Posts: 3580
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 485

Kudos [?]: 2802 [0], given: 359

### Show Tags

27 Jan 2008, 13:36
Expert's post
leizermike wrote:
4. Five pieces of wood have an average length of 124 cm and a median length of 140cm. what is the maximum possible length of the shortest piece of wood?
The correct answer is 100cm

7-t28169
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

CEO
Joined: 17 Nov 2007
Posts: 3580
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 485

Kudos [?]: 2802 [0], given: 359

### Show Tags

27 Jan 2008, 13:40
Expert's post
leizermike wrote:
5. Machine A produces pencils at a constant rate of 9000/hour. Machine B produces pencils at a constant rate of 7000/hour. If the two machines together must produce 100,000 pencils, and if each machine can operate for at most 8 hours, what is the least amount of time that machine B must operate.
The correct answer is 4 hours.

7-t57640

And, please, post OA after discussion. It will be more useful for you to see not only right ways but also wrong ones...
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Intern
Joined: 23 Jan 2008
Posts: 1
Followers: 0

Kudos [?]: 1 [1] , given: 0

### Show Tags

27 Jan 2008, 14:49
1
KUDOS
No 5.

Asume machine A takes Ta time and machine b takes TB.

then 7000*TB+9000*TA=100,000
AND TA <=8 , TB <= 8

So TA=(100-7TB)/9 <= 8 <=> TB >= 4

So machine b will operate for minimum 4 hours
CEO
Joined: 21 Jan 2007
Posts: 2756
Location: New York City
Followers: 9

Kudos [?]: 650 [0], given: 4

### Show Tags

27 Feb 2008, 23:15
walker wrote:
leizermike wrote:
5. Machine A produces pencils at a constant rate of 9000/hour. Machine B produces pencils at a constant rate of 7000/hour. If the two machines together must produce 100,000 pencils, and if each machine can operate for at most 8 hours, what is the least amount of time that machine B must operate.
The correct answer is 4 hours.

7-t57640

And, please, post OA after discussion. It will be more useful for you to see not only right ways but also wrong ones...

We want to maximize A so that we can minimize B.
9,000*8 = 72,000

This implies we have 100,000 – 72,000= 28,000 remaining

Work/Rate = Time
28,000/7,000 = 4 hours
_________________

You tried your best and you failed miserably. The lesson is 'never try'. -Homer Simpson

SVP
Joined: 29 Aug 2007
Posts: 2492
Followers: 65

Kudos [?]: 669 [0], given: 19

### Show Tags

28 Feb 2008, 02:33
walker wrote:
leizermike wrote:
3. The symbol * represents one of four arithmetic options, plus, minus, divide, or multiply. Is (5*6)*2 = 5*(6*2)?
i) 5*6 = 6*6
ii) 2*0 = 2
The correct answer is a, statement i alone is sufficient.

I think It have to be 5*6=6*5.

(5*6)*2 = 5*(6*2) is true for "+", "*" and is false for "-", "/"

1. 5*6=6*5 is true for "+", "*". sufficient.
2. 2*0=2 is true for "+", "-".insufficient.

walker, 5*6=6*5 is true for "+", "x" but how is that suff?

if * is "x", suff.
if * is "+", insuff.
_________________
CEO
Joined: 17 Nov 2007
Posts: 3580
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 485

Kudos [?]: 2802 [0], given: 359

### Show Tags

28 Feb 2008, 03:23
Expert's post
GMAT TIGER wrote:
walker, 5*6=6*5 is true for "+", "x" but how is that suff?

if * is "x", suff.
if * is "+", insuff.

plus: (5+6)+2 = 5+(6+2) true
multiply: (5x6)x2 = 5x(6x2) true
minus: (5-6)-2 = 5-(6-2) false
divide: (5/6)/2 = 5/(6/2) false

1. 5*6=6*5:
plus: (5+6) = (6+5) true
multiply: (5x6) = (6x5) true
minus: (5-6) = (6-5) false
divide: (5/6) = (6/5) false
Therefore, condition 1 points that * could be + or x. For both operations (5*6)*2 = 5*(6*2) is true. So, information is sufficient to answer the question.

2. 2*0=2:
plus: (2+0) = 2 true
multiply: (2x0) = 2 false
minus: (2-0) = 2 true
divide: (2/0) = 2 false

Therefore, condition 2 points that * could be + or -. For each operations (5*6)*2 = 5*(6*2) can be true (+) or false (-). So, information is not sufficient to answer the question.
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Display posts from previous: Sort by