Integers

This topic has expert replies
Master | Next Rank: 500 Posts
Posts: 150
Joined: Tue Mar 08, 2011 4:38 am
Thanked: 5 times

Integers

by finance » Thu Sep 08, 2011 1:34 pm
John spent a total of 135 dollars for his tickets. Field tickets cost 12 dollars each and 5 dollars each ticket for the balcony. What is the MIN. amount he could have spent for 12 dollar tickets?

- 48
-60
-84
-96
-120

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2621
Joined: Mon Jun 02, 2008 3:17 am
Location: Montreal
Thanked: 1090 times
Followed by:355 members
GMAT Score:780

by Ian Stewart » Thu Sep 08, 2011 1:59 pm
finance wrote:John spent a total of 135 dollars for his tickets. Field tickets cost 12 dollars each and 5 dollars each ticket for the balcony. What is the MIN. amount he could have spent for 12 dollar tickets?

- 48
-60
-84
-96
-120
The minimum amount he could have spent on $12 tickets is $0. He could have bought 27 balcony tickets.

If we are to assume he actually bought *some* $12 tickets, then if f represents the number of field tickets, and b the number of balcony tickets, we know:

12f + 5b = 135
12f = 135 - 5b

5 is a factor of the right side of this equation, so must be a factor of the left side, and so must be a factor of 12f. Thus f must be divisible by 5, and the smallest possible value of f is 5, and the smallest amount John could have spent on field tickets is 5*12 = 60 dollars.

Since the numbers are relatively straightforward here, you can also easily test each answer choice; when you subtract the amount spent on field tickets from 135, you must get a multiple of 5 (since balcony tickets cost 5 dollars apiece).
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com

User avatar
Legendary Member
Posts: 582
Joined: Tue Mar 08, 2011 12:48 am
Thanked: 61 times
Followed by:6 members
GMAT Score:740

by force5 » Thu Sep 08, 2011 2:00 pm
$60 should be the minimum

User avatar
Master | Next Rank: 500 Posts
Posts: 143
Joined: Sat Nov 06, 2010 9:06 pm
Thanked: 10 times
Followed by:1 members

by edvhou812 » Thu Sep 08, 2011 9:41 pm
Easy. 12 times a number needs to be a multiple of 5 in order to spend the remainder on 5 dollar tickets. 12*5=60 is the lowest possible amount. Of course Ian raises a good point that 0 should have been an option. That would have tricked quite a few people and would have been very GMATish.
I don't know what to say, really. Three minutes to the biggest battle of our professional lives. You find out life's this game of inches, so is football. Because in either game - life or football - the margin for error is so small. I mean, one half a step too late or too early and you don't quite make it. One half second too slow, too fast and you don't quite catch it. I'll tell you this, in any fight it's the guy whose willing to die whose gonna win that inch. That's football guys, that's all it is. Now, what are you gonna do?

Master | Next Rank: 500 Posts
Posts: 150
Joined: Tue Mar 08, 2011 4:38 am
Thanked: 5 times

by finance » Fri Sep 09, 2011 3:47 am
I did the same u guys did, but the OA is 120. I have been studying for two months and I have my exam on Monday. I solved 800 score's and MGMT's full tests, but I wish I did no go through unsafe sites from which I bought the test containing the previous question.

User avatar
Legendary Member
Posts: 582
Joined: Tue Mar 08, 2011 12:48 am
Thanked: 61 times
Followed by:6 members
GMAT Score:740

by force5 » Fri Sep 09, 2011 4:36 am
Hi Finance, happy to see your progress. I wish you all the luck for your exam.

Since you raised a point of unsafe sites. I would like to take this opportunity to tell everyone, including people who are following me, to be very careful in dealing with these third party vendors. Remember this is not an official Gmat material. Further, Hacks claim that this material was hacked from the GMAT database some time back. Just to update you on this - GMAT clearly claims that they have already deleted material that was compromised. Further, after the claim and law suit on the HACKS, Gmat also clearly stated that anyone found using these websites or their material will be banned permanent from giving GMAT. Till August 2010, if you would open gmathacks website you would be directed to an official site that would caution you to not use such material. I think now it has been settled (since i don't get redirected anymore)
Still the authenticity of the material is doubtful. As Eric mentioned in one of his posts that we are still sure how the material is because our students hardly use it.
To conclude i would advice people to stick to authentic and reliable source for questions since these questions are constantly reviewed by experts. Remember correct question leads to a better understanding.

All the best