GMAT Changed on April 16th - Read about the latest changes here

It is currently 23 May 2018, 04:04

Close

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
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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

It takes 3 tons of copper ore and 5 tons of iron ore to make o

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

1 KUDOS received
Intern
Intern
avatar
Joined: 09 Aug 2015
Posts: 1
It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 09 Aug 2015, 06:38
1
This post received
KUDOS
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

77% (01:00) correct 23% (01:06) wrong based on 141 sessions

HideShow timer Statistics

It takes 3 tons of copper ore and 5 tons of iron ore to make one ton of alloy A. How many tons of alloy A can be made from 60 tons of copper ore and 90 tons of iron ore?

(A) 18
(B) 18 3/4
(C) 20
(D) 30
(E) 50
Senior Manager
Senior Manager
User avatar
B
Joined: 28 Jun 2015
Posts: 297
Concentration: Finance
GPA: 3.5
Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 09 Aug 2015, 09:29
3c + 5i = a
60c + 90i = ?

20(3c + 5i) = 60c + 100i = 20a, so the answer has to be less than 20 since we are dealing with 90i.

But, 18(3c + 5i) = 54c + 90i = 18a, here we get 54c < 60c. So answer must be 18 3/4 (B).
_________________

I used to think the brain was the most important organ. Then I thought, look what’s telling me that.

Manager
Manager
avatar
Joined: 10 Nov 2014
Posts: 51
Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 10 Aug 2015, 04:04
FireStorm wrote:
3c + 5i = a
60c + 90i = ?

20(3c + 5i) = 60c + 100i = 20a, so the answer has to be less than 20 since we are dealing with 90i.

But, 18(3c + 5i) = 54c + 90i = 18a, here we get 54c < 60c. So answer must be 18 3/4 (B).


why not A
if you produce 18 3/4 the copper is not enough.
Senior Manager
Senior Manager
avatar
Joined: 15 Sep 2011
Posts: 345
Location: United States
WE: Corporate Finance (Manufacturing)
GMAT ToolKit User
Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 10 Aug 2015, 04:28
IMO, this is a max/min problem, where the amount of alloy A is limited to how much material we have. Since we need more iron ore to make alloy A than we do from copper ore, iron ore is limiting factor, and therefore, we have enough iron ore only to make 18 tons of alloy A. Answer A.
Senior Manager
Senior Manager
User avatar
B
Joined: 28 Jun 2015
Posts: 297
Concentration: Finance
GPA: 3.5
Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 11 Aug 2015, 04:33
applebus wrote:
FireStorm wrote:
3c + 5i = a
60c + 90i = ?

20(3c + 5i) = 60c + 100i = 20a, so the answer has to be less than 20 since we are dealing with 90i.

But, 18(3c + 5i) = 54c + 90i = 18a, here we get 54c < 60c. So answer must be 18 3/4 (B).


why not A
if you produce 18 3/4 the copper is not enough.


Yes, none of the given options works perfectly. But the answer must be between 18 and 20, so I chose 18 3/4, although it doesn't fit all too well.
_________________

I used to think the brain was the most important organ. Then I thought, look what’s telling me that.

Manager
Manager
avatar
Joined: 08 May 2015
Posts: 101
GMAT 1: 630 Q39 V38
GMAT 2: 670 Q44 V38
GMAT 3: 750 Q49 V44
Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 11 Aug 2015, 07:08
It's an alloy, so you need both metals to make it. If you had 150 tons of copper ore you would not be able to make any amount of the alloy, you would just have copper ore. Therefore, the answer is A.
Expert Post
2 KUDOS received
Veritas Prep GMAT Instructor
User avatar
P
Joined: 16 Oct 2010
Posts: 8071
Location: Pune, India
Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 11 Aug 2015, 22:44
2
This post received
KUDOS
Expert's post
1
This post was
BOOKMARKED
Yes, you need copper ore:iron ore in the ratio 3:5. Total 8 tons of the mix in this ratio will give 1 ton of alloy A.
If you have 60 tons of copper ore, it is enough for 60/3 = 20 tons of alloy A.
If you have 90 tons of iron ore, it is enough for 90/5 = 18 tons of alloy A.

Since iron ore is available for only 18 tons of alloy A, you can make only 18 tons of alloy A.
The leftover copper ore alone cannot make any alloy A and hence will be leftover only.

Answer must be 18.

(A)

Note: This reminds me of our maximum power of 6 in 40! kind of questions. We have many 2s but fewer 3s. We can make only as many 6s as the number of 3s we have. The leftover 2s alone cannot make a 6. Makes sense?
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

Non-Human User
User avatar
Joined: 09 Sep 2013
Posts: 6814
Premium Member
Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o [#permalink]

Show Tags

New post 12 May 2018, 22:07
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.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Re: It takes 3 tons of copper ore and 5 tons of iron ore to make o   [#permalink] 12 May 2018, 22:07
Display posts from previous: Sort by

It takes 3 tons of copper ore and 5 tons of iron ore to make o

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.