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

It is currently 19 Sep 2014, 10:30

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

The temperature of a certain cup of coffee 10 minutes after

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Manager
Manager
User avatar
Joined: 27 May 2007
Posts: 128
Followers: 1

Kudos [?]: 2 [0], given: 0

The temperature of a certain cup of coffee 10 minutes after [#permalink] New post 12 Aug 2007, 11:45
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

80% (01:51) correct 20% (01:10) wrong based on 50 sessions
The temperature of a certain cup of coffee 10 minutes after it was poured was 120 degrees Fahrenheit. If the temperature F of the coffee t minutes after it was poured can be determined by the formula F=120(2^-at) + 60, where F is in degrees Fahrenheit and a is a constant. Then the temperature of the coffee 30 minutes after it was poured was how many degrees Fahrenheit?

A. 65
B. 75
C. 80
D. 85
E. 90
[Reveal] Spoiler: OA
Director
Director
avatar
Joined: 30 Jun 2007
Posts: 793
Followers: 1

Kudos [?]: 104 [0], given: 0

GMAT Tests User
 [#permalink] New post 12 Aug 2007, 13:56
Answer: B
The temperature of coffee 10 minutes after it was poured (120 F) will help in solving the constant “a”.
120 = 120(2 ^ 10a) + 60
2 ^ -1 = 2 ^ 10a
a = -1/10
The temperature of coffee 30 minutes after it was poured is:
F = 120 ( 2 ^ -30/10) + 60
F = 120 * 1/ 8 + 60
F = 15 + 60
F = 75
Manager
Manager
User avatar
Joined: 27 May 2007
Posts: 128
Followers: 1

Kudos [?]: 2 [0], given: 0

 [#permalink] New post 12 Aug 2007, 14:33
You're right - OA is B.

When I see a problem that looks this complex, and I'm being timed, I think my brain freezes. Seriously, it's hard to think straight and just plow through it. I'm worried about how much time it will take to solve, and should I spend that much time, etc. Less than a week to go, I really need to get my speed up.
  [#permalink] 12 Aug 2007, 14:33
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic A certain population of bacteria doubles every 10 minutes. Bunuel 4 05 Jan 2014, 12:05
4 Experts publish their posts in the topic The temperature of a certain cup of coffee 10 minutes after kilukilam 7 28 Jul 2010, 08:11
The temperature of a certain cup of coffee 10 minutes after Hermione 4 11 Nov 2006, 23:16
The temperature of a cup of coffee 10 minutes after it was chadhazen6 7 03 Oct 2006, 16:43
The temperature of a certain cup of coffee 10 minutes after vivek123 3 24 Apr 2006, 05:38
Display posts from previous: Sort by

The temperature of a certain cup of coffee 10 minutes after

  Question banks Downloads My Bookmarks Reviews Important topics  


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

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®.