experts plz help

Expert replies

runzun: Senior | Next Rank: 100 Posts; Posts: 31; Joined: Wed Dec 29, 2010 11:22 pm

by runzun » Sun Aug 21, 2011 5:37 pm

This table lists enrollment in an afterschool program by activity. There are 30 total students enrolled in the entire program. Students may participate in one, two, or three activities. How many students participate in all three activities?

(1) 21 students only participate in one activity.

(2) 6 students participate in both basketball and math.

OA is A.. but i am not able to understand the logic..
plz help
Activity enrollment

basketball 19
math 12
wrestling 11

sorry for the confusion

Last edited by runzun on Mon Aug 22, 2011 5:13 pm, edited 1 time in total.

Like this post

Source: Beat The GMAT — Data Sufficiency | Sun Aug 21, 2011 5:37 pm

GmatKiss: Legendary Member; Posts: 2789; Joined: Tue Jul 26, 2011 12:19 amFollowed by: 43 members; Location: Chennai, India; Thanked: 206 times; GMAT Score:640

by GmatKiss » Mon Aug 22, 2011 1:51 am

runzun wrote:This table lists enrollment in an afterschool program by activity. There are 30 total students enrolled in the entire program. Students may participate in one, two, or three activities. How many students participate in all three activities?

(1) 21 students only participate in one activity.

(2) 6 students participate in both basketball and math.

OA is A.. but i am not able to understand the logic..
plz help

"This table lists" is this attached! am unable to view this attachment!

Like this post

GMAT/MBA Expert

Whitney Garner: GMAT Instructor; Posts: 273; Joined: Tue Sep 21, 2010 5:37 amFollowed by: 74 members; Location: Durham, NC; Thanked: 154 times; GMAT Score:770

by Whitney Garner » Mon Aug 22, 2011 8:39 am

runzun wrote:This table lists enrollment in an afterschool program by activity. There are 30 total students enrolled in the entire program. Students may participate in one, two, or three activities. How many students participate in all three activities?

(1) 21 students only participate in one activity.

(2) 6 students participate in both basketball and math.

OA is A.. but i am not able to understand the logic..
plz help

runzun:

Please include the entire question. With only the information given in the quote above, the answer would be E. (either the OA is wrong or something is missing).

Whit

Whitney Garner
GMAT/GRE/EA Instructor & Anxiety/Accommodations Coach
www.whitneygarner.com

Contributor to Beat The GMAT!

Math is a lot like love - a simple idea that can easily get complicated

Like this post

runzun: Senior | Next Rank: 100 Posts; Posts: 31; Joined: Wed Dec 29, 2010 11:22 pm

by runzun » Mon Aug 22, 2011 9:35 am

If we add up the participants in each activity, we have a total of 42 students. This discrepancy is accounted for by the fact that some students may participate in multiple activities.Since only 30 are enrolled, this means 12 places must be accounted for.

(1) If 21 students only participate in one activity, then 9 participate in multiple activities. However, we must account for 12 spaces. This means that 3 students are triple counted (12 - 9), and 6 are double counted. Therefore, 3 students participate in all three activities. To solve this using algebra, set D = the number of students in 2 activities and T = the number of students in all 3:

D + T = 9

21 + 2D + 3T = 42 {This accounts for the double and triple counting of students in multiple activities}
2D + 3T = 21

Combining the two equations, we get:
2(9 - T) + 3T = 21
18 - 2T+ 3T = 21
T = 3
SUFFICIENT

(2) The limitation of this statement is that it does not tell us how many of those 6 students, if any, also wrestle. It is possible that all 6 students participate in all activities. This would account for the table. Alternately, perhaps these 6 students only participate in these two activities, and another 6 students participate in a different pair of activities. We cannot reach a definitive conclusion.
INSUFFICIENT.

The credited response is (A) Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

this is the explanation but I am unable to understand..
plz help

Like this post

sl750: Master | Next Rank: 500 Posts; Posts: 496; Joined: Tue Jun 07, 2011 5:34 amFollowed by: 1 member; Thanked: 38 times

by sl750 » Mon Aug 22, 2011 10:02 am

Umm.. Where is the table??

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

559 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (560 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review