• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Reach higher with Artificial Intelligence. Guaranteed
Now free for 30 days

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

Mr Ben leaves his house for work

This topic has 1 expert reply and 0 member replies

Top Member

lheiannie07 Legendary Member
Joined
07 Sep 2017
Posted:
710 messages
Followed by:
4 members

Mr Ben leaves his house for work

Sun Nov 05, 2017 1:08 pm
Mr Ben leaves his house for work at exactly 8:00 AM every morning. When he averages 40 miles per hour, he arrives at his workplace three minutes late. When he averages 60 miles per hour, he arrives three minutes early. At what average speed, in miles per hour, should Mr. Ben drive to arrive at his workplace precisely on time?

A) 45
B) 48
C) 50
D) 55
E) 58

In what equation will give me the Best option in this problem?

OA B

GMAT/MBA Expert

GMATGuruNY GMAT Instructor
Joined
25 May 2010
Posted:
14043 messages
Followed by:
1813 members
13060
GMAT Score:
790
Sun Nov 05, 2017 2:13 pm
lheiannie07 wrote:
Mr Ben leaves his house for work at exactly 8:00 AM every morning. When he averages 40 miles per hour, he arrives at his workplace three minutes late. When he averages 60 miles per hour, he arrives three minutes early. At what average speed, in miles per hour, should Mr. Ben drive to arrive at his workplace precisely on time?

A) 45
B) 48
C) 50
D) 55
E) 58
Let t = the number of minutes allotted for Mr. Ben to arrive at work on time..

When he averages 40 miles per hour, he arrives at his workplace three minutes late.
(40 miles/1 hour)(1 hour/60 seconds) = 40/60 mile per minute = 2/3 mile per minute.
Since Mr. Ben arrives 3 minutes LATE, he travels for 3 minutes MORE than the allotted number of minutes:
t+3.
At a rate of 2/3 mile per minutes, the distance traveled in t+3 minutes = rt = (2/3)(t+3) = (2/3)t + 2.

When he averages 60 miles per hour, he arrives three minutes early.
(60 miles/1 hour)(1 hour/60 seconds) = 60/60 mile per minute = 1 mile per minute.
Since Mr. Ben arrives 3 minutes EARLY, he travels for 3 minutes LESS than the allotted number of minutes:
t-3.
At a rate of 1 mile per minute, the distance traveled in t-3 minutes = rt = (1)(t-3) = t-3.

Since the distance traveled in each case is THE SAME, the expressions in blue are equal:
(2/3)t + 2 = t-3
5 = (1/3)t
t = 15.

Since Mr. Ben travels for t-3 minutes at a rate of 1 mile per minute, the distance to work = (r)(t-3) = (1)(15-3) = 12 miles.
To travel the 12 miles to work in the allotted number of minutes -- the red value above -- the required rate = d/t = 12/15 = 4/5 mile per minute.
(4/5 miles/1 minute)(60 minutes/1 hour) = 48 miles per hour.

_________________
Mitch Hunt
GMAT Private Tutor
GMATGuruNY@gmail.com
If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon.
Available for tutoring in NYC and long-distance.

Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now.

Best Conversation Starters

1 lheiannie07 76 topics
2 LUANDATO 59 topics
3 ardz24 52 topics
4 AAPL 46 topics
5 M7MBA 45 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 Jeff@TargetTestPrep

Target Test Prep

141 posts
2 Brent@GMATPrepNow

GMAT Prep Now Teacher

136 posts
3 GMATGuruNY

The Princeton Review Teacher

134 posts
4 Rich.C@EMPOWERgma...

EMPOWERgmat

129 posts
5 Scott@TargetTestPrep

Target Test Prep

110 posts
See More Top Beat The GMAT Experts