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 Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

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

Show Tags

21 Feb 2014, 18:34

1

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

45% (medium)

Question Stats:

67% (03:10) correct
33% (02:38) wrong based on 172 sessions

HideShow timer Statistics

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?

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
_________________

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.

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

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.

Could the values be multiplied by 10 to avoid working with decimals?

Thanks

Yes - 625, 250 and 7000 if you want to avoid decimals. It does make the numbers much larger and that I don't like but it is up to you.
_________________

There’s something in Pacific North West that you cannot find anywhere else. The atmosphere and scenic nature are next to none, with mountains on one side and ocean on...

This month I got selected by Stanford GSB to be included in “Best & Brightest, Class of 2017” by Poets & Quants. Besides feeling honored for being part of...

Joe Navarro is an ex FBI agent who was a founding member of the FBI’s Behavioural Analysis Program. He was a body language expert who he used his ability to successfully...