BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

prep question

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 141
Joined: Wed Mar 28, 2007 9:24 pm
Thanked: 2 times
Followed by:1 members

prep question

by jamesk486 » Wed May 23, 2007 12:11 pm

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

A subway train made eleven stops on its route. If an average(arith mean) of 30 passagenters boarded at each of the first 9 stops and at each stop, begining with the 2nd, 5 fewer passengers boraded than at the previous stop, how many passengers boarded the train at the first stop?

A. 60
B. 50
C. 30
D. 20
E. 10
Top
Source: — Problem Solving |
User avatar
Community Manager
Posts: 789
Joined: Sun Jan 28, 2007 3:51 pm
Location: Silicon valley, California
Thanked: 30 times
Followed by:1 members

Re: prep question

by jayhawk2001 » Wed May 23, 2007 2:09 pm
jamesk486 wrote:A subway train made eleven stops on its route. If an average(arith mean) of 30 passagenters boarded at each of the first 9 stops and at each stop, begining with the 2nd, 5 fewer passengers boraded than at the previous stop, how many passengers boarded the train at the first stop?

A. 60
B. 50
C. 30
D. 20
E. 10
Use arithmetic progression for this. We know sum of people who boarded
on the first 9 stops = 9*30 = 270.

Sum = n/2 ( 2a + (n-1)d) -- a = first term, n = num terms, d = difference

270 = 9/2 * (2a + 8*(-5))
60 = 2a - 40
a = 50

Hence B
Top
Legendary Member
Posts: 559
Joined: Tue Mar 27, 2007 1:29 am
Thanked: 5 times
Followed by:2 members

by Cybermusings » Fri May 25, 2007 5:26 am
Yup thats the best approach
Top

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 8083
Joined: Sat Apr 25, 2015 10:56 am
Location: Los Angeles, CA
Thanked: 43 times
Followed by:29 members

Re: prep question

by Scott@TargetTestPrep » Mon May 25, 2020 11:07 am
jamesk486 wrote: ↑
Wed May 23, 2007 12:11 pm
 A subway train made eleven stops on its route. If an average(arith mean) of 30 passagenters boarded at each of the first 9 stops and at each stop, begining with the 2nd, 5 fewer passengers boraded than at the previous stop, how many passengers boarded the train at the first stop?

A. 60
B. 50
C. 30
D. 20
E. 10
Solution:

Since at each stop, beginning with the second, 5 fewer passengers boarded the train than at the previous stop, the number of passengers boarding the train at each of the first nine stops forms an evenly-spaced set. Therefore, the 5th stop must have the median, or the average, number of passengers, which is 30. So, the 4th stop has 35, the third has 40, the second has 45, and finally, the first stop has 50 passengers.

Answer: B

Scott Woodbury-Stewart
Founder and CEO
[email protected]

Image

See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews

ImageImage
Top
Post new topic Post Reply
• Page 1 of 1