Last visit was: 26 Apr 2026, 05:46 It is currently 26 Apr 2026, 05:46
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: 26 Apr 2026
Posts: 109,836
Own Kudos:
811,353
 [8]
Given Kudos: 105,893
Products:
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,836
Kudos: 811,353
 [8]
Kudos
Add Kudos
8
Bookmarks
Bookmark this Post
User avatar
sudeshpatodiya
Joined: 10 Jan 2014
Last visit: 05 Apr 2021
Posts: 89
Own Kudos:
108
 [1]
Given Kudos: 57
Location: India
Concentration: General Management, Finance
WE:General Management (Transportation)
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
Wsd65798
Joined: 16 Feb 2020
Last visit: 08 Nov 2022
Posts: 6
Own Kudos:
11
 [4]
Given Kudos: 28
Status:Active
Location: India
Concentration: Finance, General Management
GPA: 4
WE:Other (Law)
Posts: 6
Kudos: 11
 [4]
3
Kudos
Add Kudos
Bookmarks
Bookmark this Post
User avatar
stne
Joined: 27 May 2012
Last visit: 25 Apr 2026
Posts: 1,811
Own Kudos:
2,093
 [1]
Given Kudos: 679
Posts: 1,811
Kudos: 2,093
 [1]
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Wsd65798
Max Speed = 300 MPH
Speed reduces by 20 MPH after every 50 Miles. This means that in order for the plane to lose all its speed, the plane has to travel 750 miles.
750 is arrived at by considering the fact that in order for the plane to lose all 300 MPH of speed, it would need 15 intervals of 20 MPH speed losses (300/20). Since the plane needs 15 intervals to lose all the speed, it will have to travel 15 stretches of 50 Miles. Therefore, 750 = 15*50 or 300/20*50

Based on the above, the function can be arrived as m = 750 - (50/20)s
m = 750 - (5/2)s (Option C)

Hi Wsd65798,
Thank you for your solution , but what you have arrived at is option B and NOT option C.
Simplifying your equation in terms of s we would get :
\(\frac{5}{2}s=-m+750\)
Simplifying further we get =\( \frac{-2}{5}m+300\) (Option B )

So to verify that option B is correct :
Let current Speed be 300
Then after 50 miles it's speed should be 280 (reduced by 20 )
putting m=50 in option B we get S=280

Bunuel IMO option B should be the OA.
avatar
DachauerDon
Joined: 19 Apr 2025
Last visit: 27 Aug 2025
Posts: 29
Own Kudos:
Given Kudos: 26
Location: Germany
Schools: LBS
Schools: LBS
Posts: 29
Kudos: 19
Kudos
Add Kudos
Bookmarks
Bookmark this Post
B and C are equivalent equations.

s is equal to the initial speed it was going before beginning to decrease (300) minus the amount decreased (i.e. the amount of 50mile intervals covered within m miles, times the 20mph reduction for each interval). Thus: s=300 - 20(m/50)

s=300 - 2m/5
s=-2m/5 + 300

If I use the same test as stne (s=280, such that 1 50mile interval has occurred), 280 = -2m/5+300 -> m=50 WORKS

Answer is B, although if we rearrange:
5s=1500 - 2m
2m=1500 - 5s
m=750 - 5s/2
m=-5s/2 + 750

Testing again m=-5(280)/2 + 750 -> m=50 WORKS
Answer is C.

However, based on the wording of the question, the correct answer should be C as m is a function of s. Can you confirm Bunuel ?
User avatar
Nikhils29
Joined: 14 Sep 2023
Last visit: 10 Oct 2025
Posts: 5
Given Kudos: 18
Posts: 5
Kudos: 0
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Both B and C are actually same equations.
Both are correct.
User avatar
Kinshook
User avatar
Major Poster
Joined: 03 Jun 2019
Last visit: 25 Apr 2026
Posts: 5,986
Own Kudos:
Given Kudos: 163
Location: India
GMAT 1: 690 Q50 V34
WE:Engineering (Transportation)
Products:
GMAT 1: 690 Q50 V34
Posts: 5,986
Kudos: 5,860
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Once a certain airplane attains its maximum speed of 300 miles per hour (mph), it begins decreasing speed as it approaches its destination. After every 50 miles, the plane decreases its airspeed by 20 mph.

Which of the following equations best defines the number of miles the plane has traveled (m) after beginning to decrease speed as a function of the airplane’s airspeed (s)?

Airplane's speed s = 300 - 20m/50 = (300 - 2m/5) mph
s = 300 - 2m/5
2m/5 = 300 - s
m = 5*300/2 - 5s/2 = 750 - 5s/2

IMO C
Moderators:
Math Expert
109836 posts
Tuck School Moderator
852 posts