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

 It is currently 03 May 2016, 01:12

### 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

# In assembling a Bluetooth device, a factory uses one of two kinds of

Author Message
TAGS:

### Hide Tags

Intern
Joined: 19 Feb 2013
Posts: 10
Followers: 0

Kudos [?]: 4 [0], given: 1

In assembling a Bluetooth device, a factory uses one of two kinds of [#permalink]

### Show Tags

21 Feb 2014, 18:34
00:00

Difficulty:

45% (medium)

Question Stats:

71% (03:12) correct 29% (02:12) wrong based on 68 sessions

In assembling a Bluetooth device, a factory uses one of two kinds of modules. One module costs $6.25 and the other one, that is cheaper, costs$2.50. The factory holds a $70 worth stock of 22 modules. How many of the modules in the stock are of the cheaper kind? (A) 4 (B) 8 (C) 12 (D) 16 (E) 18 [Reveal] Spoiler: OA Manager Joined: 19 Apr 2013 Posts: 78 Concentration: Entrepreneurship, Finance GMAT Date: 06-05-2015 GPA: 3.88 WE: Programming (Computer Software) Followers: 2 Kudos [?]: 64 [0], given: 9 Re: In assembling a Bluetooth device, a factory uses one of two kinds of [#permalink] ### Show Tags 21 Feb 2014, 23:21 anujtsingh wrote: In assembling a Bluetooth device, a factory uses one of two kinds of modules. One module costs$6.25 and the other one, that is cheaper, costs $2.50. The factory holds a$70 worth stock of 22 modules. How many of the modules in the stock are of the cheaper kind?

(A)4
(B)8
(C)12
(D)16
(E)18

It is easy go : consider x is count of costlier module. y is count of cheaper module.

6.25*x + 2.5*y = 70;
x+y = 22;

by solving these two equation we get y = 18
_________________

Thanks,
AB

+1 Kudos if you like and understand.

SVP
Joined: 17 Jul 2014
Posts: 1562
Location: United States
GMAT 1: 550 Q39 V27
GMAT 2: 560 Q42 V26
GMAT 3: 560 Q43 V24
GMAT 4: 650 Q49 V30
GPA: 3.56
WE: General Management (Transportation)
Followers: 9

Kudos [?]: 148 [0], given: 100

Re: In assembling a Bluetooth device, a factory uses one of two kinds of [#permalink]

### Show Tags

01 Nov 2015, 12:13
i believe it is a 700 lvl question just because it involves decimals.
a+b=22
6.25a + 2.5b = 70 / multiply by 4
find b:
25a+10b = 280
a=22-b
25(22-b)+10b = 280
550-25b+10b = 280
550-280 = 15b
270 = 15b
b = 270/15
b=18.
Senior Manager
Joined: 12 Sep 2015
Posts: 334
Followers: 21

Kudos [?]: 224 [0], given: 4

Re: In assembling a Bluetooth device, a factory uses one of two kinds of [#permalink]

### Show Tags

01 Nov 2015, 14:27
anujtsingh wrote:
In assembling a Bluetooth device, a factory uses one of two kinds of modules. One module costs $6.25 and the other one, that is cheaper, costs$2.50. The factory holds a $70 worth stock of 22 modules. How many of the modules in the stock are of the cheaper kind? (A) 4 (B) 8 (C) 12 (D) 16 (E) 18 We can also solve the question using ONE VARIABLE. Let x = the number of cheap modules So, 22 - x = the number of expensive modules So, the VALUE of the cheap modules = 2.5x So, the VALUE of the cheap expensive = 6.25(22 - x) The TOTAL value = 70 dollars, so we can write: 2.5x + 6.25(22 - x) = 70 Expand to get: 2.5x + 137.5 - 6.25x = 70 Simplify: -3.75x + 137.5 = 70 Rearrange to get: -3.75x = -67.5 Solve: x = 18 Answer: E Aside: Here's a free video on deciding how many variables to assign on questions like this: http://www.gmatprepnow.com/module/gmat- ... /video/906 Cheers, Brent _________________ Brent Hanneson - Founder of GMAT Prep Now, a free & comprehensive GMAT course with: - over 500 videos (35 hours of instruction) - over 800 practice questions - 2 full-length practice tests and other bonus offers - http://www.gmatprepnow.com/ Veritas Prep GMAT Instructor Joined: 16 Oct 2010 Posts: 6480 Location: Pune, India Followers: 1759 Kudos [?]: 10492 [0], given: 206 Re: In assembling a Bluetooth device, a factory uses one of two kinds of [#permalink] ### Show Tags 01 Nov 2015, 21:46 Expert's post anujtsingh wrote: In assembling a Bluetooth device, a factory uses one of two kinds of modules. One module costs$6.25 and the other one, that is cheaper, costs $2.50. The factory holds a$70 worth stock of 22 modules. How many of the modules in the stock are of the cheaper kind?

(A) 4
(B) 8
(C) 12
(D) 16
(E) 18

Shortlist the options by using approximation and then logic will get you to the answer.

Cost of one module is 6.25 and of the other is 2.50. The average cost of the total modules = 70/20 = approx 3.5. It is a bit less than 3.5 because actually the number of modules is 22, not 20. So the average is way closer to 2.50 and hence out of 22, many more modules are the cheaper variety. So only possible options are 16 and 18.
Now note that with 16 modules of $2.50, you will get the total cost as 40 but if remaining 6 modules are of cost$6.25 each, you will not get a whole number for total cost. But the total cost is $70 - a whole number. So the number of$2.50 modules must be 18 so that the leftover 4 modules are of $6.25 which will give a whole number. Answer (E) _________________ Karishma Veritas Prep | GMAT Instructor My Blog Get started with Veritas Prep GMAT On Demand for$199

Veritas Prep Reviews

Re: In assembling a Bluetooth device, a factory uses one of two kinds of   [#permalink] 01 Nov 2015, 21:46
Similar topics Replies Last post
Similar
Topics:
8 One-fifth of the batteries produced by an upstart factory are defectiv 6 26 Nov 2014, 07:56
26 In the Land of Oz only one or two-letter words are used. The 14 02 Jun 2012, 02:38
45 Company S produces two kinds of stereos: basic and deluxe. 18 08 Sep 2010, 11:20
8 Company S produces two kinds of stereos: basic and deluxe. 6 29 Dec 2009, 05:45
4 A factory that employs 1000 assembly line workers pays each 11 07 Nov 2009, 03:10
Display posts from previous: Sort by