NEW HERE? LEARN MORE
closeclose
Last visit was: 26 Apr 2024, 01:00 It is currently 26 Apr 2024, 01:00
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

A car was initially traveling at an average speed of 48 miles per hour

SORT BY:
Date
Kudos
Tags:
Find Similar Topics 
Show Tags
Hide Tags
User avatar
S
Maria240895chile
Manager
Manager
Joined: 23 Apr 2021
Posts: 127
Own Kudos [?]: 41 [2]
Given Kudos: 115
Send PM
A car was initially traveling at an average speed of 48 miles per hour [#permalink] New post   Updated on: 31 Jan 2023, 14:24
2
Bookmarks
00:00
A
B
C
D
E

Difficulty:

35% (medium)

Question Stats:

73% (02:17) correct 27% (02:28) wrong based on 131 sessions
Hide Show timer Statistics
A car was initially traveling at an average speed of 48 miles per hour. During each of ten successive 10-minute intervals, the car decreased its average speed by 4 miles per hour. How many miles did the car travel in the seventh 10-minute interval?

(A) 2
(B) 3
(C) 4
(D) 5
(E) 6
ShowHide Answer
Official Answer
C

Originally posted by Maria240895chile on 31 Jan 2023, 14:16.
Last edited by Bunuel on 31 Jan 2023, 14:24, edited 1 time in total.
Renamed the topic and edited the question.
User avatar
L
stne
SVP
SVP
Joined: 27 May 2012
Posts: 1680
Own Kudos [?]: 1424 [2]
Given Kudos: 632
Send PM
Re: A car was initially traveling at an average speed of 48 miles per hour [#permalink] New post   05 Feb 2023, 01:39
1
Kudos
1
Bookmarks
Maria240895chile wrote:
A car was initially traveling at an average speed of 48 miles per hour. During each of ten successive 10-minute intervals, the car decreased its average speed by 4 miles per hour. How many miles did the car travel in the seventh 10-minute interval?

(A) 2
(B) 3
(C) 4
(D) 5
(E) 6


During the 7th, \(10 \)min interval its speed was \(24\) miles per hour.

Travelling at \(24\) miles per hour the car would go \(4\) miles in \(10\) minutes.

Ans C

Hope it's clear.
User avatar
G
SaquibHGMATWhiz
GMATWhiz Representative
Joined: 23 May 2022
Posts: 640
Own Kudos [?]: 429 [0]
Given Kudos: 6
Location: India
GMAT 1: 760 Q51 V40
Send PM
Re: A car was initially traveling at an average speed of 48 miles per hour [#permalink] New post   05 Feb 2023, 04:39
Expert Reply
Maria240895chile wrote:
A car was initially traveling at an average speed of 48 miles per hour. During each of ten successive 10-minute intervals, the car decreased its average speed by 4 miles per hour. How many miles did the car travel in the seventh 10-minute interval?

(A) 2
(B) 3
(C) 4
(D) 5
(E) 6


Solution:

  • Speed in the first 10 mins \(=48\) mph
  • Speed in the second 10 mins \(=44\) mph
  • Speed in the third 10 mins \(=40\) mph
    • Is there a pattern? Yes
    • The magnitude of speed is in AP with first term \(a=48\) and common difference \(d=-4\)
  • Speed in the seventh 10 mins \(=a+(n-1)d=48+(7-1)(-4)=48-24=24\) mph
  • So, distance traveled in the seventh 10 mins \(=speed\times time=24\times \frac{10}{60}=4\) miles

Hence the right answer is Option C
User avatar
B
Kjamiru
Intern
Intern
Joined: 24 Mar 2023
Posts: 2
Own Kudos [?]: 0 [0]
Given Kudos: 0
Send PM
Re: A car was initially traveling at an average speed of 48 miles per hour [#permalink] New post   27 Mar 2023, 20:10
long time reader first time commenter here. I understand how to answer the question. But my question here is why would the first interval be 48 instead of 44 MPH. is there technical wording from the question that I am missing?
User avatar
L
KarishmaB
Tutor
Joined: 16 Oct 2010
Posts: 14823
Own Kudos [?]: 64926 [0]
Given Kudos: 426
Location: Pune, India
Send PM
Re: A car was initially traveling at an average speed of 48 miles per hour [#permalink] New post   28 Mar 2023, 00:20
Expert Reply
Kjamiru wrote:
long time reader first time commenter here. I understand how to answer the question. But my question here is why would the first interval be 48 instead of 44 MPH. is there technical wording from the question that I am missing?


The wording of the question is a bit suspect.

The car starts out at 48 mph. During each of ten successive 10-minute intervals, the car decreased its average speed by 4 miles per hour. So the average speed starts going down and by the end of the first 10 min interval, it would be 44 mph. I would think that the decrease may be uniform over the interval such that the average speed during the interval is say 46 mph. But we are not given what the average speed during the interval is. The decrease needn't be uniform.

The speed at the start of the 7th interval will be 24 mph and will go down to 20 mph by the end of the 7th interval. The question implies that the speed reduces by 4 mph at the end of the interval.
GMAT Club Bot
gmatclubot
Re: A car was initially traveling at an average speed of 48 miles per hour [#permalink]
28 Mar 2023, 00:20
Moderators:
Bunuel
Math Expert
92918 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