Last visit was: 15 Jul 2024, 01:57 It is currently 15 Jul 2024, 01:57
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.
Close
Request Expert Reply
Confirm Cancel
SORT BY:
Date
Math Expert
Joined: 02 Sep 2009
Posts: 94343
Own Kudos [?]: 640911 [22]
Given Kudos: 85011
Send PM
Most Helpful Reply
Retired Moderator
Joined: 08 Dec 2013
Status:Greatness begins beyond your comfort zone
Posts: 2093
Own Kudos [?]: 8978 [19]
Given Kudos: 171
Location: India
Concentration: General Management, Strategy
GPA: 3.2
WE:Information Technology (Consulting)
Send PM
General Discussion
Board of Directors
Joined: 11 Jun 2011
Status:QA & VA Forum Moderator
Posts: 6049
Own Kudos [?]: 4764 [2]
Given Kudos: 463
Location: India
GPA: 3.5
WE:Business Development (Commercial Banking)
Send PM
Retired Moderator
Joined: 22 Jun 2014
Posts: 970
Own Kudos [?]: 3925 [2]
Given Kudos: 182
Location: India
Concentration: General Management, Technology
GMAT 1: 540 Q45 V20
GPA: 2.49
WE:Information Technology (Computer Software)
Send PM
Re: A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
1
Kudos
1
Bookmarks
Distnace covered in 1.5 hr (90 minutes i.e. between 09:00AM - 10:30AM ) = 60 miles (40 * 1.5)

Second covered 60 miles in 80 minutes (i.e. 10 minutes less than the first car because second car started at 09:10AM).

Speed of the second car = 60miles / (80/60) hour = 45miles/hour

Option A is correct.
GMAT Club Legend
GMAT Club Legend
Joined: 08 Jul 2010
Status:GMAT/GRE Tutor l Admission Consultant l On-Demand Course creator
Posts: 6020
Own Kudos [?]: 13781 [3]
Given Kudos: 125
Location: India
GMAT: QUANT+DI EXPERT
Schools: IIM (A) ISB '24
GMAT 1: 750 Q51 V41
WE:Education (Education)
Send PM
Re: A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
3
Bookmarks
Expert Reply
Bunuel wrote:
A car going at 40 miles per hour set out on an 80-mile trip at 9:00 A.M. Exactly 10 minutes later, a second car left from the same place and followed the same route. How fast, in miles per hour, was the second car going if it caught up with the first car at 10:30 A.M.?

(A) 45

(B) 50

(C) 53

(D) 55

(E) 60


Distance travelled by first car in 10 mins = 40/6 = 20/3 miles

Relative Distance between two cars at the time second car starts = 20/3 miles

Relative speed of two cars = (s-14) where s is the speed of second car

Time taken by second car to catch first car = (9:10 to 10:30) = 1 hour 20 mins = 4/3 hours

Relative speed = Relative Distance / time

(s-40) = (20/3)/(4/3) = 5
i.e. s = 5+40 = 45 miles per hour

Answer: Option A
Manager
Manager
Joined: 17 Aug 2015
Posts: 77
Own Kudos [?]: 67 [1]
Given Kudos: 196
Send PM
Re: A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
1
Bookmarks
Here is one other way to solve the problem.
Car 1 took 90 minutes to cover some distance, whereas the second car took 80 minutes to do the same. We can set up following equation-
Ratio of time = inverse of the ratio of speed
80/90 = 40/x => 2/90=1/x=> x = 45m.

the problem can also be solved by the relative speed equation
distance to be caught up by the second car is equal to the distance that the first car did in first 10 minutes
40/60*10
This is to be caught up in 80 minutes or 8/6 hours
40/60*10/(x-40) = 8/6. Solve this to get x = 45.
Target Test Prep Representative
Joined: 14 Oct 2015
Status:Founder & CEO
Affiliations: Target Test Prep
Posts: 19130
Own Kudos [?]: 22631 [3]
Given Kudos: 286
Location: United States (CA)
Send PM
A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
1
Kudos
2
Bookmarks
Expert Reply
Bunuel wrote:
A car going at 40 miles per hour set out on an 80-mile trip at 9:00 A.M. Exactly 10 minutes later, a second car left from the same place and followed the same route. How fast, in miles per hour, was the second car going if it caught up with the first car at 10:30 A.M.?

(A) 45

(B) 50

(C) 53

(D) 55

(E) 60


We are given that a car left at 9 a.m. traveling at a rate of 40 mph and another car left 10 minutes later. Since the second car caught up to the first car at 10:30 a.m., the time of the first car is 1.5 hours and the distance is 1.5 x 40 = 60 miles.

If we let r = the rate of the second car, the distance of the second car is:

r x (1 hour 20 minutes)

r x (1 1/3 hours)

r x (4/3) = 4r/3

Since the second car catches up to the first car we can set the distances equal and determine r:

4r/3 = 60

4r = 180

r = 45

Answer: A
Manager
Manager
Joined: 22 Nov 2016
Posts: 203
Own Kudos [?]: 275 [0]
Given Kudos: 50
Concentration: Leadership, Strategy
Send PM
A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
Very little calculation here.
The second car travelled for 80 minutes and covered 60 miles. The question asks the speed of the second car in miles per hour. OR
How many miles did the second car travel in 60mins?

80mins------60miles
60mins------?
\(\frac{(60*60)}{80}\) = \(\frac{(3600)}{80}\) = slightly over 40 but less than 50

Answer is A
Manager
Manager
Joined: 02 Jan 2017
Posts: 53
Own Kudos [?]: 7 [0]
Given Kudos: 23
Location: India
Schools: Oxford "21
Send PM
Re: A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
Bunuel wrote:
A car going at 40 miles per hour set out on an 80-mile trip at 9:00 A.M. Exactly 10 minutes later, a second car left from the same place and followed the same route. How fast, in miles per hour, was the second car going if it caught up with the first car at 10:30 A.M.?

(A) 45

(B) 50

(C) 53

(D) 55

(E) 60


Hi GMATPrepNow

COuld you please help me with this solution . I got the realtive distance of the gap as 20/3 miles. I am not sure how to proceed next
VP
VP
Joined: 10 Jul 2019
Posts: 1385
Own Kudos [?]: 577 [0]
Given Kudos: 1656
Send PM
A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
Concept: when the 2 cars depart from the same place, and the 2nd Car catches up to the 1st Car —-

Distance car 1 travels = Distance car 2 travels


Car 1 travels for 3/2 hours (from 9 AM to 10:30 AM) at a Speed of 40 mph



Car 2 drives for 10 minutes less, so the travel Time for Car 2 is:

(3/2) - (1/6) = 8/6 = 4/3 hours

Car 2’s Unknown Speed = R


Distance = Speed * Time


Again, when the 2 cars Meet—-

D of Car 1 = D of Car 2

40 * (3/2) = R * (4/3)

R = (3 * 40 * 3) / (2 * 4)

R = 3 * 5 * 3 = 45 mph

-A-

Posted from my mobile device
User avatar
Non-Human User
Joined: 09 Sep 2013
Posts: 33970
Own Kudos [?]: 851 [0]
Given Kudos: 0
Send PM
Re: A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
GMAT Club Bot
Re: A car going at 40 miles per hour set out on an 80-mile trip at 9:00 [#permalink]
Moderator:
Math Expert
94343 posts