NEW HERE? LEARN MORE
closeclose
Last visit was: 26 Apr 2024, 15:13 It is currently 26 Apr 2024, 15:13
Decision Tracker
My Rewards
New posts
New comers' posts

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.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel

The Ryder family trave1ed at an average rate of 60 miles per hour(mph)

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
L
Bunuel
Math Expert
Joined: 02 Sep 2009
Posts: 92948
Own Kudos [?]: 619237 [2]
Given Kudos: 81609
Send PM
CAT Tests Forum Quiz Mode
The Ryder family trave1ed at an average rate of 60 miles per hour(mph) [#permalink] New post   26 Oct 2020, 07:46
1
Kudos
1
Bookmarks
Expert Reply
00:00
A
B
C
D
E

Difficulty:

15% (low)

Question Stats:

85% (02:00) correct 15% (02:10) wrong based on 64 sessions
Hide Show timer Statistics
The Ryder family traveled at an average rate of 60 miles per hour(mph), and it took 10 hours to complete their trip. If they trave1ed for 4 of their 10 hours at a constant speed of 70 mph, at what average speed did they trave1 for the remaining 6 hours to obtain the 60 mph average for the entire trip?

A. 53 1/3 mph
B. 53 2/3 mph
C. 54 1/3 mph
D. 55 1/3 mph
E. 55 2/3 mph
ShowHide Answer
Official Answer
A
User avatar
G
Mona2019
Manager
Manager
Joined: 13 Mar 2018
Posts: 194
Own Kudos [?]: 205 [0]
Given Kudos: 1608
Send PM
Re: The Ryder family trave1ed at an average rate of 60 miles per hour(mph) [#permalink] New post   26 Oct 2020, 08:11
Average speed is distance travelled/time taken
\(\frac{(4*70 + 6*x) }{10}=60\)

\(x =\frac{160}{3}=53*\frac{1}{3}\)

IMO A
User avatar
L
IanStewart
GMAT Tutor
Joined: 24 Jun 2008
Posts: 4128
Own Kudos [?]: 9247 [1]
Given Kudos: 91
 Q51  V47
Send PM
Re: The Ryder family trave1ed at an average rate of 60 miles per hour(mph) [#permalink] New post   26 Oct 2020, 08:14
1
Kudos
Expert Reply
You could use weighted average principles here, since average speed is a weighted average, weighted by time (and a bit unusually for an average speed problem, this question gives us all of our times). But doing that doesn't save much time, because the numbers don't work out too cleanly, and it's straightforward just to work out our remaining distance and time. In 10 hours at 60 mph, the distance traveled is 600 miles. In 4 hours at 70 mph, the distance traveled is 280 miles. So the remaining 320 miles were covered in 6 hours, at a speed of 320/6 = 160/3 = 53 1/3 mph.
User avatar
S
Target4bschool
Manager
Manager
Joined: 29 Dec 2019
Posts: 67
Own Kudos [?]: 60 [0]
Given Kudos: 181
Schools: IE MiM (Sep 21 Start) (A)
Send PM
Re: The Ryder family trave1ed at an average rate of 60 miles per hour(mph) [#permalink] New post   26 Oct 2020, 11:58
IanStewart could you please show how to do it with weighted average?

Posted from my mobile device
User avatar
L
IanStewart
GMAT Tutor
Joined: 24 Jun 2008
Posts: 4128
Own Kudos [?]: 9247 [0]
Given Kudos: 91
 Q51  V47
Send PM
Re: The Ryder family trave1ed at an average rate of 60 miles per hour(mph) [#permalink] New post   26 Oct 2020, 13:35
Expert Reply
Using alligation, you'd draw this number line:

---A-------60-----------------70----

and because the times are in a 4 to 6, or 2 to 3 ratio, the distances to the middle average are in a 2 to 3 ratio. Since the larger distance is 10, the smaller distance is thus 2/3 of that, or 20/3, and A = 60 - (20/3) = 53 1/3.

That's a weighted average solution using alligation -- if you solve weighted average problems algebraically, the solution would essentially be the one I posted above.
User avatar
P
gmatcafe
Manager
Manager
Joined: 27 Sep 2020
Posts: 191
Own Kudos [?]: 195 [0]
Given Kudos: 97
Location: Uzbekistan
Concentration: Finance, Strategy
Schools: Marshall '25 Smeal Carey Ross '25
GPA: 3.73
WE:Consulting (Consulting)
Send PM
Re: The Ryder family trave1ed at an average rate of 60 miles per hour(mph) [#permalink] New post   26 Oct 2020, 21:12
Bunuel wrote:
The Ryder family traveled at an average rate of 60 miles per hour(mph), and it took 10 hours to complete their trip. If they trave1ed for 4 of their 10 hours at a constant speed of 70 mph, at what average speed did they trave1 for the remaining 6 hours to obtain the 60 mph average for the entire trip?

A. 53 1/3 mph
B. 53 2/3 mph
C. 54 1/3 mph
D. 55 1/3 mph
E. 55 2/3 mph


4*70+6*x=60*10
280+6x=600
6x=320
3x=160
x=53 1/3 A)
GMAT Club Bot
gmatclubot
Re: The Ryder family trave1ed at an average rate of 60 miles per hour(mph) [#permalink]
26 Oct 2020, 21:12
Moderators:
Bunuel
Math Expert
92948 posts
yashikaaggarwal
Senior Moderator - Masters Forum
3137 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne
Main navigation
GMAT Resources
Partners
MBA Resources
www.gmac.com|www.mba.com | | GMAT Club Rules | Terms and Conditions