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

 It is currently 03 May 2015, 12:06

### 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 one alloy there is 12% chromium while in another alloy...

Author Message
TAGS:
Intern
Joined: 25 Jan 2013
Posts: 24
Followers: 0

Kudos [?]: 13 [0], given: 11

In one alloy there is 12% chromium while in another alloy... [#permalink]  21 Feb 2013, 06:54
1
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

84% (02:34) correct 16% (02:05) wrong based on 67 sessions
In one alloy there is 12% chromium while in another alloy it is 8%. 15 kg of the first alloy was melted together with 35 kg of the second one to form a third alloy. Find the percentage of chromium in the new alloy.

A. 8.8%
B. 9%
C. 9.2%
D. 8.6%
E. 8.4%
[Reveal] Spoiler: OA
Intern
Joined: 16 Jan 2013
Posts: 23
Followers: 0

Kudos [?]: 2 [2] , given: 17

Re: In one alloy there is 12% chromium while in another alloy... [#permalink]  21 Feb 2013, 06:58
2
KUDOS
(15x.12 + 35x.08)/(15+35) x100=9.2
Math Expert
Joined: 02 Sep 2009
Posts: 27170
Followers: 4226

Kudos [?]: 40932 [1] , given: 5576

Re: In one alloy there is 12% chromium while in another alloy... [#permalink]  21 Feb 2013, 07:01
1
KUDOS
Expert's post
antoxavier wrote:
In one alloy there is 12% chromium while in another alloy it is 8%. 15 kg of the first alloy was melted together with 35 kg of the second one to form a third alloy. Find the percentage of chromium in the new alloy.

A. 8.8%
B. 9%
C. 9.2%
D. 8.6%
E. 8.4%

The amount of chromium in the new 15+35=50 kg alloy is 0.12*15+0.08*35=4.6 kg, so the percentage is 4.6/50*100=9.2%.

_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 4761
Followers: 295

Kudos [?]: 52 [0], given: 0

Re: In one alloy there is 12% chromium while in another alloy... [#permalink]  23 Mar 2015, 20:01
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.
_________________
EMPOWERgmat Instructor
Status: GMAT Assassin/Co-Founder
Affiliations: EMPOWERgmat
Joined: 19 Dec 2014
Posts: 1861
Location: United States (CA)
GMAT 1: 800 Q51 V49
GRE 1: 340 Q170 V170
Followers: 77

Kudos [?]: 491 [0], given: 37

Re: In one alloy there is 12% chromium while in another alloy... [#permalink]  23 Mar 2015, 20:23
Expert's post
Hi All,

This question is essentially a 'Weighted Average" question, so you can solve it in a few different ways. There is a built-in 'shortcut' in these types of questions that is worth noting (since it can save you some time). As long as the RATIO of the items is the same as what is described in the prompt, the amount of each item doesn't matter.

Here, we're told that we have 15kg of the first alloy and 35kg of the second. That is a ratio of 15:35, which reduces to 3:7. As long as THAT ratio is maintained, we will get the exact same answer as we would if we use 15kg and 35kg.

So, if we had 3 kg of the first alloy and 7kg of the second, the math would be a little easier. We'd have....

[3(.12) + 7(.08)]/(3+7) =
(.36 + .56)/(10) =
.92/10 =
9.2%

[Reveal] Spoiler:
C

GMAT assassins aren't born, they're made,
Rich
_________________

Rich Cohen
Rich.C@empowergmat.com
http://www.empowergmat.com

EMPOWERgmat GMAT Club Page, Study Plans, & Discounts

SVP
Status: The Best Or Nothing
Joined: 27 Dec 2012
Posts: 1858
Location: India
Concentration: General Management, Technology
WE: Information Technology (Computer Software)
Followers: 22

Kudos [?]: 876 [0], given: 193

Re: In one alloy there is 12% chromium while in another alloy... [#permalink]  25 Mar 2015, 00:18

$$\frac{\frac{12}{100} * 15 + \frac{8}{100} * 35}{35+15} * 100 = 9.2%$$
_________________

Kindly press "+1 Kudos" to appreciate

Intern
Joined: 16 Mar 2015
Posts: 9
Followers: 0

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

Re: In one alloy there is 12% chromium while in another alloy... [#permalink]  25 Mar 2015, 09:12
"In one alloy there is 12% chromium while in another alloy it is 8%. 15 kg of the first alloy was melted together with 35 kg of the second one to form a third alloy. Find the percentage of chromium in the new alloy."

The two part are melted in a ratio of 3 to 7.
Hence : (3*12% + 7*8%)/10 = 9.2%
Re: In one alloy there is 12% chromium while in another alloy...   [#permalink] 25 Mar 2015, 09:12
Similar topics Replies Last post
Similar
Topics:
12 There are 2 bars of copper-nickel alloy. One bar has 2 parts 9 07 Jul 2011, 21:12
There are two bars of gold-silver alloy; one piece has 2 5 29 May 2008, 01:15
There are two bars of gold-silver alloy; The first is 40% 1 12 Mar 2008, 10:20
There are two bars of gold-silver alloy; one piece has 2 2 11 Nov 2007, 12:05
38 There are 2 bars of gold-silver alloy; one piece has 2 parts 25 18 Jun 2007, 18:15
Display posts from previous: Sort by

# In one alloy there is 12% chromium while in another alloy...

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.