Last visit was: 20 Nov 2025, 04:55 It is currently 20 Nov 2025, 04:55
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
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 20 Nov 2025
Posts: 105,414
Own Kudos:
Given Kudos: 99,987
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,414
Kudos: 778,486
 [19]
1
Kudos
Add Kudos
18
Bookmarks
Bookmark this Post
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 20 Nov 2025
Posts: 105,414
Own Kudos:
778,486
 [2]
Given Kudos: 99,987
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 105,414
Kudos: 778,486
 [2]
Kudos
Add Kudos
2
Bookmarks
Bookmark this Post
User avatar
WholeLottaLove
Joined: 13 May 2013
Last visit: 13 Jan 2014
Posts: 305
Own Kudos:
Given Kudos: 134
Posts: 305
Kudos: 628
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
nks2611
Joined: 24 Oct 2016
Last visit: 06 Apr 2020
Posts: 189
Own Kudos:
74
 [2]
Given Kudos: 89
Location: India
Concentration: Finance, International Business
Schools: IIMB
GMAT 1: 550 Q42 V28
GPA: 3.96
WE:Human Resources (Retail Banking)
Schools: IIMB
GMAT 1: 550 Q42 V28
Posts: 189
Kudos: 74
 [2]
1
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
statement 1. as distance is constant then we can apply direct formula 2xy/x+y= average rate here x=60 and y=40 then putting the values in formula we get 2*60*40/60+40= 48km/hr. hence suff.

statement2. no info. about another rate form village to town so insuff.
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 20 Nov 2025
Posts: 21,719
Own Kudos:
27,002
 [1]
Given Kudos: 300
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 21,719
Kudos: 27,002
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
anujtsingh
In the morning, John drove to his mother's house in the village at an average speed of 60 kilometers per hour. When he was going back to town in the evening, he drove more cautiously and his speed was lower. If John went the same distance in the evening as in the morning, what was John's average speed for the entire trip?

(1) In the evening, John drove at a constant speed of 40 kilometers per hour.
(2) John's morning drive lasted 2 hours.

We are given that John drives at a rate of 60 km per hour and drives at a lesser rate when driving again later. We also are given that the distances driven are the same and need to determine the average rate.

We can use the formula:

average speed = total distance/total time

Statement One Alone:

In the evening, John drove at a constant speed of 40 kilometers per hour.

Since the distance each way is d, we can let time 1 = d/60, and time 2 = d/40; thus:

average speed = 2d/(d/60 + d/40)

average speed = 2d/(2d/120 + 3d/120)

average speed = 2d/(5d/120)

average speed = 240d/5d = 48

Statement one alone is sufficient to answer the question.

Statement Two Alone:

John's morning drive lasted 2 hours.

Knowing only the total time is not enough to determine the average speed.

Answer: A
avatar
gmatapprentice
Joined: 14 Nov 2018
Last visit: 21 Apr 2021
Posts: 50
Own Kudos:
Given Kudos: 211
Location: United Arab Emirates
Concentration: Finance, Strategy
Schools: LBS '22 (I)
GMAT 1: 590 Q42 V30
GMAT 2: 670 Q46 V36
GPA: 2.6
Schools: LBS '22 (I)
GMAT 2: 670 Q46 V36
Posts: 50
Kudos: 15
Kudos
Add Kudos
Bookmarks
Bookmark this Post
ScottTargetTestPrep

Hi, can we use the formula 2S1S2/(S1+S2) to solve st. 1?
User avatar
ScottTargetTestPrep
User avatar
Target Test Prep Representative
Joined: 14 Oct 2015
Last visit: 20 Nov 2025
Posts: 21,719
Own Kudos:
27,002
 [1]
Given Kudos: 300
Status:Founder & CEO
Affiliations: Target Test Prep
Location: United States (CA)
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 21,719
Kudos: 27,002
 [1]
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post
gmatapprentice
ScottTargetTestPrep

Hi, can we use the formula 2S1S2/(S1+S2) to solve st. 1?

As a matter of fact, you can. In the formula average speed = 2d/(d/60 + d/40) that I used above, we can factor out d in d/60 + d/40 and we will get:

2d/[d*(1/60 + 1/40)]

If we cancel d from the numerator and the denominator, we get:

2/(1/60 + 1/40)

Adding the two fractions in the denominator, we have:

2/((40 + 60)/(40*60)) = (2*40*60)/(40 + 60)

This is the exact same expression that you would get if you took S1 = 60 and S2 = 40 in your formula. You should note that this is only applicable when the distances traveled are the same for both speeds.
User avatar
bumpbot
User avatar
Non-Human User
Joined: 09 Sep 2013
Last visit: 04 Jan 2021
Posts: 38,598
Own Kudos:
Posts: 38,598
Kudos: 1,079
Kudos
Add Kudos
Bookmarks
Bookmark this Post
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.
Moderators:
Math Expert
105414 posts
496 posts