BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Speed, distance,time

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 98
Joined: Sat May 31, 2014 8:29 pmFollowed by: 2 members
Thanked: 1 times
by RiyaR » Wed Aug 27, 2014 9:01 am
Two men drove from Hartford to Boston(100miles) leaving at the same time. Mr. Clifford averaged 30miles an hour for the first 20 miles and 40 miles an hour for the rest of the journey. Mr. Sherman drove at a steady pace. They arrived at the same time. What was Mr.Sherman's average speed?
A)35.2
B)24.2
C)25
D)37.2
E)35


This was my understanding of the problem: Since they both reach at the same time we can assume that the time taken is the same. We also know that the distance is constant. So in order to find Mr.Clifford's average speed for the whole journey we can use the formula:(m+n)pq/mq+np. Can you tell me where I am going wrong in this sum? The answer seems to be D, but Im not able to arrive at it....
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
Elite Legendary Member
Posts: 10392
Joined: Sun Jun 23, 2013 6:38 pmFollowed by: 511 members
Location: Palo Alto, CA
Thanked: 2867 times
GMAT Score:800

by [email protected] » Wed Aug 27, 2014 9:09 am
Hi RiyaR,

This question gives us lots of data to work with, so solving it is really just about doing the math correctly (and in a simple way; complexity is unnecessary).

Let's start with Mr. Clifford:
-He's going to travel 100 miles.
-He travels 30mph for the first 20 miles

D = R x T
20 = 30 (T)
2/3 hr. = T

-He travels 40mph for the rest of the journey

D = R x T
80 = 40 (T)
2 hrs. = T

We now know the total time was 2/3 + 2 hours = 8/3 hours

Now we deal with Mr. Sherman:
-He's going to travel 100 miles at a CONSTANT SPEED. Using the 8/3 hours for total time, we have..

D = R x T
100 = R (8/3)
3(100)/8 = R
37.5 = R

Final Answer: [spoiler]D - I assume those ".2"s are supposed to be ".5"s[/spoiler]

GMAT assassins aren't born, they're made,
Rich
Contact Rich at [email protected]
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
GMAT Instructor
Posts: 15539
Joined: Tue May 25, 2010 12:04 pmFollowed by: 1906 members
Location: New York, NY
Thanked: 13060 times
GMAT Score:790

by GMATGuruNY » Wed Aug 27, 2014 9:24 am
RiyaR wrote:Two men drove from Hartford to Boston (100miles) leaving at the same time. Mr. Clifford averaged 30 miles an hour for the first 20 miles and 40 miles an hour for the rest of the journey. Mr. Sherman drove at a steady pace. They arrived at the same time. What was Mr.Sherman's average speed?
The distance traveled at 40mph (80 miles) is 4 times the distance traveled at 30mph (20 miles).
The total distance can be ANY VALUE, as long as the distance traveled at 40mph is 4 times the distance traveled at 30mph.

Let the distance traveled at 30mph = 30 miles and the distance traveled at 40mph = 120 miles, for a total distance of 150 miles.
Time to travel 30 miles at a speed of 30mph = d/r = 30/30 = 1 hour.
Time to travel 120 miles at a speed of 40mph = d/r = 120/40 = 3 hours.
Average speed for the entire 150 miles = d/(total time) = 150/(1+3) = 150/4 = 75/2 = 37.5 mph.
Last edited by GMATGuruNY on Wed Aug 27, 2014 10:33 am, edited 1 time in total.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.

As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.

For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Senior | Next Rank: 100 Posts
Posts: 98
Joined: Sat May 31, 2014 8:29 pmFollowed by: 2 members
Thanked: 1 times

by RiyaR » Wed Aug 27, 2014 10:30 am
Thank you so much!! I think I made an error while caluclating the figures! and yes, the 0.2 is 0.5
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1